International Journal of Materials Engineering, 2016
Synthesis of metal nanoparticles with specific properties is a newly established research area at... more Synthesis of metal nanoparticles with specific properties is a newly established research area attracting a great deal of attention. Several methods have been put forward for synthesis of these materials, namely chemical vapor condensation, arc discharge, hydrogen plasma-etal reaction, and laser pyrolysis in the vapor phase, microemulsion hydrothermal, sol-gel, sonochemical. Nanoscale lead-free soldrs (i.e., Sn-xAg [x 0 0, 20, 40, 60, 0, 100(wt%)], Sn-3.0Ag-0.5Cu, Sn-3.5Ag-0.5Cu, Sn-3.5Ag-xZn (x = 0.5 to 3.5wt%) and Sn-0.7Cu) have been investigated. For Sn-3.5Ag and Sn-3.5Ag-0.5Cu nanoparticles, the melting temperature with average size of 30nm was 210 degr. C. and 201 degr. C., much lower than that of bulk alloy. Also, Sn-Ag-Cu nanopowders showed good wttability with contact angles less than 30 degr. The peak melting temperatures of the 21nm, 18nm and 14nm Sn-0.7Cu nanoparticles were 212.9 degr. C, 207.9 degr. C and 205.2 degr. C, respectively. In this paper, the fundamentals of sy...
In the current work, applying a rotating magnetic field (RMF) is an innovative approach to improv... more In the current work, applying a rotating magnetic field (RMF) is an innovative approach to improve the microstructure features and creep resistance of Sn-2.0Ag-2.0Zn (SAZ) alloy. The results revealed that RMF does not change intermetallic compounds (IMCs) constituents furthermore SAZ alloy with applying a magnetic field (SAZ-B) exhibited microstructure refinement and homogeneous distribution of IMCs. Moreover, SAZ-B displayed more creep resistance (∼366%) and greater creep rupture time (∼56.4%) than those of SAZ alloy. These results have great implications in improving the alloy’s performance for industrial applications.
For luminescent solar concentrators (LSCs), it is important to enhance the fluorescence quantum y... more For luminescent solar concentrators (LSCs), it is important to enhance the fluorescence quantum yield (FQY) and photostability. Our measurements have demonstrated that the addition of silver nanoparticles to dye solution causes broadening of absorption bands, so the spectral range of sunlight absorbed by LSC has increased. Silver nanoparticles (NPs) were characterized by X-ray diffraction (XRD) and UV-Vis absorption spectra. UV-Vis spectrum showed a single peak at 442 nm due to the surface plasmon resonance (SPR). The position of SPR peak exhibited a red shift after the sample was exposed to UV irradiation (unfiltered light). The optical band gap values have a reduction from 2.46 to 2.37 eV after irradiation for 960 minutes. Such reduction in optical band gap may be due to change in particle size calculated using Mie theory. The photostability of organic dyes used was improved after adding silver nanoparticles. The area under fluorescence spectra of dyes with silver NPs increased by...
decrease the onset melting temperature (233 ‐ C) of this alloy to 203.5 ‐ C and 216 ‐ C, respecti... more decrease the onset melting temperature (233 ‐ C) of this alloy to 203.5 ‐ C and 216 ‐ C, respectively. The results indicate that the Sn-5Sb-1.5Au alloy has very good ultimate tensile strength (UTS), ductility, and fusion heat, which are better than both those of the Sn-5Sb-3.5Ag and Sn-5Sb alloys. The formation of intermetallic compounds (IMCs) AuSn4 and Ag3Sn enhanced the microstructure stability, while retained the formation of SbSn precipitates in the solidiflcation microstructure, thus signiflcantly improved the strength and ductility. For all alloys, both UTS and yield stress (aey) increase with increasing strain rate and decrease with increasing temperature in tensile tests, but changes of ductility are generally small with inconsistent trends.
Journal of Materials Science: Materials in Electronics
In the present study, for the first time, rotating magnetic field (RMF) was used to improve the s... more In the present study, for the first time, rotating magnetic field (RMF) was used to improve the solidification microstructure and mechanical properties of Sn–2.0Ag–0.5Cu (SAC205) solder alloy. Results revealed that the microstructure and tensile behaviour were improved. As observed, after applying RMF, grain size of β-Sn reduced to be ~ 10 μm which was decreased by ~ 60%. As well, an average size of IMCs formed in SAC205-B alloy were ~ 10–30 μm which were reduced by ~ 40–66%. Therefore, the growth rate of IMCs has been successfully suppressed with RMF. Interestingly, a decrease in grain size and IMCs thickness indicated the beneficial effect of applying RMF on the solder alloy. Consequently, in terms of tensile tests, SAC205 with RMF showed the highest strength over the entire temperatures and strain rates range. Moreover, UTS, YS, YM and El. % at room temperature (25 °C) of SAC205 alloy with RMF were ~ 9.0%, ~ 26.0%, ~ 8.0% and ~ 9.0% greater than that of RMF-free SAC205 alloy. Also, results showed that tensile strength of SAC205 alloy with and without RMF are remarkably sensitive to changes in both temperature and strain rate. Furthermore, the average stress exponent (n) and activation energy (Q) for RMF-free SAC205 and SAC205 with RMF solder alloys have been discussed. The obtained results should prove beneficial in the microelectronic packaging industry.
Abstract Studying and understanding the dendritic growth process is a challenging topic related t... more Abstract Studying and understanding the dendritic growth process is a challenging topic related to liquid-solid phase transition, as it helps to predict the final microstructure controlling the solder properties. In a specific case of the design of Sn-Bi and Sn-Bi-Cu alloys, the solidification microstructures and corresponding electrical and elastic properties were studied with and without permanent magnetic stirring (PMS), as their influence on the growth morphology of dendrites is not yet fully assessed to date. We use pulse echo overlap (PEO) method for measuring the polycrystalline bulk modulus K, Young's modulus E, shear modulus G, Poisson ratio υ and hardness H. The PMS-driven flow caused a disruption of the columnar β-Sn dendrites and columnar-to-equiaxed transition (CET). Such behavior is believed to evolve from dendrite fragmentation, arises through complex hyper-branched morphologies at the origen of Lorentz force and Seebeck effect that acting on the melt. Both the hardness and elastic modulus are increased as the Poisson's ratio decreased. Moreover, the Pugh ratio clarified the ductility behavior of the alloy samples, while Poisson's ratio and electrical resistivity display slight decrease in the ionic contribution with applying PMS and/or Cu content. These results open new ways to predict the final microstructure controlling the dendritic growth in metallic alloys.
Abstract The present paper investigates the microstructural and mechanical properties of Sn-1.0Ag... more Abstract The present paper investigates the microstructural and mechanical properties of Sn-1.0Ag-0.5Cu (SAC105) solder alloy with 0.06 wt% Ni and 0.5 wt% Sb additions. The study revealed that the microstructure properties and elastic moduli of such solder alloy improved. Results indicated that Ni element diffused from the molten solder matrix into the IMC particles to form the Ni3Sn4 IMC phase during solidification. Thus, Ni improved the solder microstructure and increased the drop lifetime of the electronic assembly. Meanwhile, by adding Sb element, no new IMCs formed due to the high solubility of Sb in Sn, but provide solid solution strengthening. In terms of tensile behavior, the SAC105–0.5Sb exhibited the highest strength and largest ductility. As well, all examined alloys exhibited higher mechanical properties with increasing strain rate and/or decreasing testing temperature. Moreover, notable improvements of 31.25% and 101.1% in elongation were obtained with addition of Ni and Sb elements, respectively. Consequently, ductility was enhanced by Ni or Sb additions. Furthermore, the average activation energy (Q) for SAC105, SAC105-0.06Ni, and SAC105-0.5Sb solders were 49, 57 and 63.5 kJ/mol, respectively, which is close to that of pipe-diffusion mechanism in Sn-based solder matrix.
Abstract Sn-Ag-Cu lead-free solders are regarded as a potential substitute for Pb-Sn solder alloy... more Abstract Sn-Ag-Cu lead-free solders are regarded as a potential substitute for Pb-Sn solder alloys. In the current study, the non-reacting, non-coarsening ZnO nano-particles (ZnO NPs) were successfully incorporated into Sn–3.0Ag–0.5Cu (SAC305) lead-free solder by mechanical mixing of ZnO powders and melting at 900 °C for 2 h. Tensile creep testing was performed for plain SAC305 solder and SAC305-0.7 wt% ZnO NPs composite solders and a Garofalo hyperbolic sine power-law relationship was created from the experimental data to predict the creep mechanism as a function of tensile stress and temperature. Based on the tensile creep results, the creep resistance of SAC305 solder alloy was improved considerably with ZnO NPs addition, although the creep lifetime was increased. From microstructure observation, reinforcing ZnO NPs into SAC305 solder substantially suppressed the enlargement of Ag 3 Sn and Cu 6 Sn 5 intermetallic compound (IMC) particles and decreased the spacing of the inter-particles between them, reduced the grain size of β-Sn and increased the eutectic area in the alloy matrix. The modification of microstructure, which leaded to a strong adsorption effect and high surface-free energy of ZnO NPs, could result in hindering the dislocation slipping, and thus provides standard dispersion strengthening mechanism. Moreover, the average activation energy (Q) for SAC305 and SAC305-0.7ZnO alloys were 50.5 and 53.1 kJ/mol, respectively, close to that of pipe diffusion mechanism in matrix Sn.
The eutectic Sn-0.7Cu solder alloy is widely used in electronic packaging in which the creep prop... more The eutectic Sn-0.7Cu solder alloy is widely used in electronic packaging in which the creep property of the solder joint is essential to meet the global demand for longer operating lifetime in their applications. In this study, the influence of Ag and In additions on tensile creep behavior and thermal properties of bulk eutectic Sn-Cu solder alloy is reported. Results show that addition of Ag and In resulted not only in the formation of new Ag 3 Sn and c-SnIn 4 intermetallic compounds (IMCs), but also in the refinement of grain size of Sn-0.7Cu solder from $0.50 to $0.15 lm. Accordingly, the creep properties of the Ag or In-containing solder alloys are notably improved. The creep strain rate increases and creep lifetime decreases as the applied stress level and temperature increase. Room and elevated-temperature creep rate of bulk Sn-Cu solder was reduced by 521.0% after Ag addition, but for In addition the reduction was about 200.7%. These differences are attributed to the presence of new Ag 3 Sn and c-SnIn 4 precipitates and their rules in classical dispersion strengthening as a separate phases. Moreover, the eutectic temperature of Sn-0.7Cu is decreased from 227.4 to 217.8 and 224.0°C with the addition of Ag and In, respectively.
The eutectic Sn-0.7Cu solder alloy is widely used in electronic packaging in which the creep prop... more The eutectic Sn-0.7Cu solder alloy is widely used in electronic packaging in which the creep property of the solder joint is essential to meet the global demand for longer operating lifetime in their applications. In this study, the influence of Ag and In additions on tensile creep behavior and thermal properties of bulk eutectic Sn-Cu solder alloy is reported. Results show that addition of Ag and In resulted not only in the formation of new Ag 3 Sn and c-SnIn 4 intermetallic compounds (IMCs), but also in the refinement of grain size of Sn-0.7Cu solder from $0.50 to $0.15 lm. Accordingly, the creep properties of the Ag or In-containing solder alloys are notably improved. The creep strain rate increases and creep lifetime decreases as the applied stress level and temperature increase. Room and elevated-temperature creep rate of bulk Sn-Cu solder was reduced by 521.0% after Ag addition, but for In addition the reduction was about 200.7%. These differences are attributed to the presence of new Ag 3 Sn and c-SnIn 4 precipitates and their rules in classical dispersion strengthening as a separate phases. Moreover, the eutectic temperature of Sn-0.7Cu is decreased from 227.4 to 217.8 and 224.0°C with the addition of Ag and In, respectively.
It is important, for electronic application, to decrease the melting point of Sn-5Sb solder alloy... more It is important, for electronic application, to decrease the melting point of Sn-5Sb solder alloy because it is relatively high as compared with the most popular eutectic Pb-Sn solder alloy. Adding Au or Ag can decrease the onset melting temperature (233 • C) of this alloy to 203.5 • C and 216 • C, respectively. The results indicate that the Sn-5Sb-1.5Au alloy has very good ultimate tensile strength (UTS), ductility, and fusion heat, which are better than both those of the Sn-5Sb-3.5Ag and Sn-5Sb alloys. The formation of intermetallic compounds (IMCs) AuSn 4 and Ag 3 Sn enhanced the microstructure stability, while retained the formation of SbSn precipitates in the solidification microstructure, thus significantly improved the strength and ductility. For all alloys, both UTS and yield stress (σ y) increase with increasing strain rate and decrease with increasing temperature in tensile tests, but changes of ductility are generally small with inconsistent trends.
a b s t r a c t Minor alloying addition to solders has been an important strategy to improve the ... more a b s t r a c t Minor alloying addition to solders has been an important strategy to improve the integrity and reliability of Pb-free solders joint. In this study, the effects of 0.06Ni and 0.5Sb additives on the microstructure and solidification behavior as well as the creep properties of Sn–1.0Ag–0.5Cu (SAC105) alloys were investi-gated. Results show that alloying of Ni and Sb resulted in considerably reduced undercooling, increased eutectic area and extended volume fraction of proeutectic Sn of which the dendritic size was refined. Moreover, with the addition of Ni and Sb into SAC105, significant improvement in creep resistance of (210%) and (350%) is realized when compared with the SAC105 solder alloy. Likewise, the creep life time of SAC105 alloys was remarkably enhanced (2–3 times) with the minor alloying additions. An analysis of the creep behavior at elevated temperatures suggested that the presence of hard Ni 3 Sn 4 IMC particles and the solid solution hardening effects whi...
... and low cost, which makes them attractive as lead-free solder materials for electronic applic... more ... and low cost, which makes them attractive as lead-free solder materials for electronic applications [1]. However, despite early encouraging results, there is now a wide body of literature confirming that bulk Zn-containing alloys suffer from an inherently poor oxidation resistance ...
Full implementation of the new generation of lead-free solders requires detailed knowledge and un... more Full implementation of the new generation of lead-free solders requires detailed knowledge and understanding of their mechanical behavior. This paper reports on structure, thermal and tensile creep properties of Sn-5 wt.%Sb, Sn-5 wt.%Sb-3.5 wt.%Ag, and Sn-5 wt.%Sb-1.5 wt.%Au lead-free solder alloys. The results show that the microstructure of Sn-5Sb alloy is characterized by the presence of cubed intermetallic compound (IMC) of SbSn particles (<5 m) within -Sn matrix. The two ternary alloys exhibit additional constituent phases of IMCs Ag 3 Sn for Sn-5Sb-3.5Ag and AuSn 4 for Sn-5Sb-1.5Au alloys. Attention has been paid to the role of IMCs on creep behavior. The tensile creep tests were performed within the temperature range 25-130 • C at constant applied stresses. Activation energy (Q) and stress exponent (n) were determined to clarify the deformation mechanism. This study revealed that the solder alloy Sn-5Sb-1.5Au have potential to gave a good combination of higher creep resistance and rupture time, lower melting temperature and higher fusion heat compared with the other two alloys.
ABSTRACT Nowadays, a major concern of Sn–Cu based solder alloys is focused on continuously improv... more ABSTRACT Nowadays, a major concern of Sn–Cu based solder alloys is focused on continuously improving the comprehensive properties of solder joints formed between the solders and substrates. In this study, the influence of Ag and/or In doping on the microstructures and tensile properties of eutectic Sn–0.7Cu lead free solder alloy have been investigated. Also, the effects of temperature and strain rate on the mechanical performance of Sn–0.7Cu, Sn–0.7Cu–2Ag, Sn–0.7Cu–2In and Sn–0.7Cu–2Ag–2In solders were investigated. The tensile tests showed that while the ultimate tensile strength (UTS) and yield stress (YS) increased with increasing strain rate, they decreased with increasing temperature, showing strong strain rate and temperature dependence. The results also revealed that with the addition of Ag and In into Sn–0.7Cu, significant improvement in YS (∼255%) and UTS (∼215%) is realized when compared with the other commercially available Sn–0.7wt. % Cu solder alloys. Furthermore, the Sn–0.7Cu–2Ag–2In solder material developed here also exhibits higher ductility and well-behaved mechanical performance than that of eutectic Sn–0.7Cu commercial solder. Microstructural analysis revealed that the origen of change in mechanical properties is attributed to smaller β-Sn dendrite grain dimensions and formation of new inter-metallic compounds (IMCs) in the ternary and quaternary alloys.
ABSTRACT In this study, the effects of separate and dual additions of small amount of Cu, In and ... more ABSTRACT In this study, the effects of separate and dual additions of small amount of Cu, In and Ag on the microstructure and elastic properties as well as thermal behavior of the eutectic Sn–9Zn solder alloy were investigated. The elastic properties of the newly developed ternary and quaternary alloys have been investigated using sound wave velocity measurements at 4 MHz and T = 25 °C. In particular, the hardness, the attenuation coefficient, the bulk and shear moduli, Young&amp;#39;s and Poisson&amp;#39;s ratio have been established for a range of alloy compositions. Results showed that alloying of Cu, In and Ag resulted in reducing fusion heat, solidus temperature and broadening the pasty range. Moreover, the presence of additional elements in Sn–Zn alloy system allows many complex intermetallic (IMC) phases to form. Both the hardness and reduced modulus increase as the Poisson&amp;#39;s ratio of the alloy decreases. The elastic properties can be correlated with the formation of the new IMC phases. By analyzing the quotient of shear modulus to bulk modulus, we can assume that the Sn–9Zn, Sn–9Zn–1.5Ag and Sn–9Zn–0.7Cu alloys are ductile solders whereas, the Sn–9Zn–1.5In and Sn–9Zn–1.5Ag–0.7Cu alloys are brittle in nature.
Full implementation of the new generation of lead-free solders requires detailed knowledge and un... more Full implementation of the new generation of lead-free solders requires detailed knowledge and understanding of their mechanical behavior. This paper reports on structure, thermal and tensile creep properties of Sn-5 wt.%Sb, Sn-5 wt.%Sb-3.5 wt.%Ag, and Sn-5 wt.%Sb-1.5 wt.%Au lead-free solder alloys. The results show that the microstructure of Sn-5Sb alloy is characterized by the presence of cubed intermetallic compound (IMC) of SbSn particles (<5 m) within -Sn matrix. The two ternary alloys exhibit additional constituent phases of IMCs Ag 3 Sn for Sn-5Sb-3.5Ag and AuSn 4 for Sn-5Sb-1.5Au alloys. Attention has been paid to the role of IMCs on creep behavior. The tensile creep tests were performed within the temperature range 25-130 • C at constant applied stresses. Activation energy (Q) and stress exponent (n) were determined to clarify the deformation mechanism. This study revealed that the solder alloy Sn-5Sb-1.5Au have potential to gave a good combination of higher creep resistance and rupture time, lower melting temperature and higher fusion heat compared with the other two alloys.
The present work is concerned with studying the synthesis and characterization of hybrid aluminum... more The present work is concerned with studying the synthesis and characterization of hybrid aluminum bronze matrix strengthened with nano-aluminum oxide particles (n-Al2O3), and carbon nano tubes (CNTs). The selected matrix composite was successfully incorporated with different weighted percentages of CNTs (i.e. 1.0 and 2.0 wt.%) and/or n-Al2O3 (i.e. 1.0 and 2.0 wt.%) by sintering process. From the microstructure analysis, n- Al2O3 particles was dispersed uniformly and holding over the surface of aluminum bronze. Furthermore, some agglomeration was found due to reinforced CNTs into aluminum bronze matrix. From hardness tests, it was found that incorporated n- Al2O3 and CNTs into matrix increased the hardness of composites to be equal 230 HV, which is around 2.3 times higher than that of an aluminum bronze matrix. Moreover, the wear loss of CNTs - Al2O3/aluminum bronze composites diminished because of the impact of homogeneous circulation of CNTs in aluminum bronze and low corrosion coe...
International Journal of Materials Engineering, 2016
Synthesis of metal nanoparticles with specific properties is a newly established research area at... more Synthesis of metal nanoparticles with specific properties is a newly established research area attracting a great deal of attention. Several methods have been put forward for synthesis of these materials, namely chemical vapor condensation, arc discharge, hydrogen plasma-etal reaction, and laser pyrolysis in the vapor phase, microemulsion hydrothermal, sol-gel, sonochemical. Nanoscale lead-free soldrs (i.e., Sn-xAg [x 0 0, 20, 40, 60, 0, 100(wt%)], Sn-3.0Ag-0.5Cu, Sn-3.5Ag-0.5Cu, Sn-3.5Ag-xZn (x = 0.5 to 3.5wt%) and Sn-0.7Cu) have been investigated. For Sn-3.5Ag and Sn-3.5Ag-0.5Cu nanoparticles, the melting temperature with average size of 30nm was 210 degr. C. and 201 degr. C., much lower than that of bulk alloy. Also, Sn-Ag-Cu nanopowders showed good wttability with contact angles less than 30 degr. The peak melting temperatures of the 21nm, 18nm and 14nm Sn-0.7Cu nanoparticles were 212.9 degr. C, 207.9 degr. C and 205.2 degr. C, respectively. In this paper, the fundamentals of sy...
In the current work, applying a rotating magnetic field (RMF) is an innovative approach to improv... more In the current work, applying a rotating magnetic field (RMF) is an innovative approach to improve the microstructure features and creep resistance of Sn-2.0Ag-2.0Zn (SAZ) alloy. The results revealed that RMF does not change intermetallic compounds (IMCs) constituents furthermore SAZ alloy with applying a magnetic field (SAZ-B) exhibited microstructure refinement and homogeneous distribution of IMCs. Moreover, SAZ-B displayed more creep resistance (∼366%) and greater creep rupture time (∼56.4%) than those of SAZ alloy. These results have great implications in improving the alloy’s performance for industrial applications.
For luminescent solar concentrators (LSCs), it is important to enhance the fluorescence quantum y... more For luminescent solar concentrators (LSCs), it is important to enhance the fluorescence quantum yield (FQY) and photostability. Our measurements have demonstrated that the addition of silver nanoparticles to dye solution causes broadening of absorption bands, so the spectral range of sunlight absorbed by LSC has increased. Silver nanoparticles (NPs) were characterized by X-ray diffraction (XRD) and UV-Vis absorption spectra. UV-Vis spectrum showed a single peak at 442 nm due to the surface plasmon resonance (SPR). The position of SPR peak exhibited a red shift after the sample was exposed to UV irradiation (unfiltered light). The optical band gap values have a reduction from 2.46 to 2.37 eV after irradiation for 960 minutes. Such reduction in optical band gap may be due to change in particle size calculated using Mie theory. The photostability of organic dyes used was improved after adding silver nanoparticles. The area under fluorescence spectra of dyes with silver NPs increased by...
decrease the onset melting temperature (233 ‐ C) of this alloy to 203.5 ‐ C and 216 ‐ C, respecti... more decrease the onset melting temperature (233 ‐ C) of this alloy to 203.5 ‐ C and 216 ‐ C, respectively. The results indicate that the Sn-5Sb-1.5Au alloy has very good ultimate tensile strength (UTS), ductility, and fusion heat, which are better than both those of the Sn-5Sb-3.5Ag and Sn-5Sb alloys. The formation of intermetallic compounds (IMCs) AuSn4 and Ag3Sn enhanced the microstructure stability, while retained the formation of SbSn precipitates in the solidiflcation microstructure, thus signiflcantly improved the strength and ductility. For all alloys, both UTS and yield stress (aey) increase with increasing strain rate and decrease with increasing temperature in tensile tests, but changes of ductility are generally small with inconsistent trends.
Journal of Materials Science: Materials in Electronics
In the present study, for the first time, rotating magnetic field (RMF) was used to improve the s... more In the present study, for the first time, rotating magnetic field (RMF) was used to improve the solidification microstructure and mechanical properties of Sn–2.0Ag–0.5Cu (SAC205) solder alloy. Results revealed that the microstructure and tensile behaviour were improved. As observed, after applying RMF, grain size of β-Sn reduced to be ~ 10 μm which was decreased by ~ 60%. As well, an average size of IMCs formed in SAC205-B alloy were ~ 10–30 μm which were reduced by ~ 40–66%. Therefore, the growth rate of IMCs has been successfully suppressed with RMF. Interestingly, a decrease in grain size and IMCs thickness indicated the beneficial effect of applying RMF on the solder alloy. Consequently, in terms of tensile tests, SAC205 with RMF showed the highest strength over the entire temperatures and strain rates range. Moreover, UTS, YS, YM and El. % at room temperature (25 °C) of SAC205 alloy with RMF were ~ 9.0%, ~ 26.0%, ~ 8.0% and ~ 9.0% greater than that of RMF-free SAC205 alloy. Also, results showed that tensile strength of SAC205 alloy with and without RMF are remarkably sensitive to changes in both temperature and strain rate. Furthermore, the average stress exponent (n) and activation energy (Q) for RMF-free SAC205 and SAC205 with RMF solder alloys have been discussed. The obtained results should prove beneficial in the microelectronic packaging industry.
Abstract Studying and understanding the dendritic growth process is a challenging topic related t... more Abstract Studying and understanding the dendritic growth process is a challenging topic related to liquid-solid phase transition, as it helps to predict the final microstructure controlling the solder properties. In a specific case of the design of Sn-Bi and Sn-Bi-Cu alloys, the solidification microstructures and corresponding electrical and elastic properties were studied with and without permanent magnetic stirring (PMS), as their influence on the growth morphology of dendrites is not yet fully assessed to date. We use pulse echo overlap (PEO) method for measuring the polycrystalline bulk modulus K, Young's modulus E, shear modulus G, Poisson ratio υ and hardness H. The PMS-driven flow caused a disruption of the columnar β-Sn dendrites and columnar-to-equiaxed transition (CET). Such behavior is believed to evolve from dendrite fragmentation, arises through complex hyper-branched morphologies at the origen of Lorentz force and Seebeck effect that acting on the melt. Both the hardness and elastic modulus are increased as the Poisson's ratio decreased. Moreover, the Pugh ratio clarified the ductility behavior of the alloy samples, while Poisson's ratio and electrical resistivity display slight decrease in the ionic contribution with applying PMS and/or Cu content. These results open new ways to predict the final microstructure controlling the dendritic growth in metallic alloys.
Abstract The present paper investigates the microstructural and mechanical properties of Sn-1.0Ag... more Abstract The present paper investigates the microstructural and mechanical properties of Sn-1.0Ag-0.5Cu (SAC105) solder alloy with 0.06 wt% Ni and 0.5 wt% Sb additions. The study revealed that the microstructure properties and elastic moduli of such solder alloy improved. Results indicated that Ni element diffused from the molten solder matrix into the IMC particles to form the Ni3Sn4 IMC phase during solidification. Thus, Ni improved the solder microstructure and increased the drop lifetime of the electronic assembly. Meanwhile, by adding Sb element, no new IMCs formed due to the high solubility of Sb in Sn, but provide solid solution strengthening. In terms of tensile behavior, the SAC105–0.5Sb exhibited the highest strength and largest ductility. As well, all examined alloys exhibited higher mechanical properties with increasing strain rate and/or decreasing testing temperature. Moreover, notable improvements of 31.25% and 101.1% in elongation were obtained with addition of Ni and Sb elements, respectively. Consequently, ductility was enhanced by Ni or Sb additions. Furthermore, the average activation energy (Q) for SAC105, SAC105-0.06Ni, and SAC105-0.5Sb solders were 49, 57 and 63.5 kJ/mol, respectively, which is close to that of pipe-diffusion mechanism in Sn-based solder matrix.
Abstract Sn-Ag-Cu lead-free solders are regarded as a potential substitute for Pb-Sn solder alloy... more Abstract Sn-Ag-Cu lead-free solders are regarded as a potential substitute for Pb-Sn solder alloys. In the current study, the non-reacting, non-coarsening ZnO nano-particles (ZnO NPs) were successfully incorporated into Sn–3.0Ag–0.5Cu (SAC305) lead-free solder by mechanical mixing of ZnO powders and melting at 900 °C for 2 h. Tensile creep testing was performed for plain SAC305 solder and SAC305-0.7 wt% ZnO NPs composite solders and a Garofalo hyperbolic sine power-law relationship was created from the experimental data to predict the creep mechanism as a function of tensile stress and temperature. Based on the tensile creep results, the creep resistance of SAC305 solder alloy was improved considerably with ZnO NPs addition, although the creep lifetime was increased. From microstructure observation, reinforcing ZnO NPs into SAC305 solder substantially suppressed the enlargement of Ag 3 Sn and Cu 6 Sn 5 intermetallic compound (IMC) particles and decreased the spacing of the inter-particles between them, reduced the grain size of β-Sn and increased the eutectic area in the alloy matrix. The modification of microstructure, which leaded to a strong adsorption effect and high surface-free energy of ZnO NPs, could result in hindering the dislocation slipping, and thus provides standard dispersion strengthening mechanism. Moreover, the average activation energy (Q) for SAC305 and SAC305-0.7ZnO alloys were 50.5 and 53.1 kJ/mol, respectively, close to that of pipe diffusion mechanism in matrix Sn.
The eutectic Sn-0.7Cu solder alloy is widely used in electronic packaging in which the creep prop... more The eutectic Sn-0.7Cu solder alloy is widely used in electronic packaging in which the creep property of the solder joint is essential to meet the global demand for longer operating lifetime in their applications. In this study, the influence of Ag and In additions on tensile creep behavior and thermal properties of bulk eutectic Sn-Cu solder alloy is reported. Results show that addition of Ag and In resulted not only in the formation of new Ag 3 Sn and c-SnIn 4 intermetallic compounds (IMCs), but also in the refinement of grain size of Sn-0.7Cu solder from $0.50 to $0.15 lm. Accordingly, the creep properties of the Ag or In-containing solder alloys are notably improved. The creep strain rate increases and creep lifetime decreases as the applied stress level and temperature increase. Room and elevated-temperature creep rate of bulk Sn-Cu solder was reduced by 521.0% after Ag addition, but for In addition the reduction was about 200.7%. These differences are attributed to the presence of new Ag 3 Sn and c-SnIn 4 precipitates and their rules in classical dispersion strengthening as a separate phases. Moreover, the eutectic temperature of Sn-0.7Cu is decreased from 227.4 to 217.8 and 224.0°C with the addition of Ag and In, respectively.
The eutectic Sn-0.7Cu solder alloy is widely used in electronic packaging in which the creep prop... more The eutectic Sn-0.7Cu solder alloy is widely used in electronic packaging in which the creep property of the solder joint is essential to meet the global demand for longer operating lifetime in their applications. In this study, the influence of Ag and In additions on tensile creep behavior and thermal properties of bulk eutectic Sn-Cu solder alloy is reported. Results show that addition of Ag and In resulted not only in the formation of new Ag 3 Sn and c-SnIn 4 intermetallic compounds (IMCs), but also in the refinement of grain size of Sn-0.7Cu solder from $0.50 to $0.15 lm. Accordingly, the creep properties of the Ag or In-containing solder alloys are notably improved. The creep strain rate increases and creep lifetime decreases as the applied stress level and temperature increase. Room and elevated-temperature creep rate of bulk Sn-Cu solder was reduced by 521.0% after Ag addition, but for In addition the reduction was about 200.7%. These differences are attributed to the presence of new Ag 3 Sn and c-SnIn 4 precipitates and their rules in classical dispersion strengthening as a separate phases. Moreover, the eutectic temperature of Sn-0.7Cu is decreased from 227.4 to 217.8 and 224.0°C with the addition of Ag and In, respectively.
It is important, for electronic application, to decrease the melting point of Sn-5Sb solder alloy... more It is important, for electronic application, to decrease the melting point of Sn-5Sb solder alloy because it is relatively high as compared with the most popular eutectic Pb-Sn solder alloy. Adding Au or Ag can decrease the onset melting temperature (233 • C) of this alloy to 203.5 • C and 216 • C, respectively. The results indicate that the Sn-5Sb-1.5Au alloy has very good ultimate tensile strength (UTS), ductility, and fusion heat, which are better than both those of the Sn-5Sb-3.5Ag and Sn-5Sb alloys. The formation of intermetallic compounds (IMCs) AuSn 4 and Ag 3 Sn enhanced the microstructure stability, while retained the formation of SbSn precipitates in the solidification microstructure, thus significantly improved the strength and ductility. For all alloys, both UTS and yield stress (σ y) increase with increasing strain rate and decrease with increasing temperature in tensile tests, but changes of ductility are generally small with inconsistent trends.
a b s t r a c t Minor alloying addition to solders has been an important strategy to improve the ... more a b s t r a c t Minor alloying addition to solders has been an important strategy to improve the integrity and reliability of Pb-free solders joint. In this study, the effects of 0.06Ni and 0.5Sb additives on the microstructure and solidification behavior as well as the creep properties of Sn–1.0Ag–0.5Cu (SAC105) alloys were investi-gated. Results show that alloying of Ni and Sb resulted in considerably reduced undercooling, increased eutectic area and extended volume fraction of proeutectic Sn of which the dendritic size was refined. Moreover, with the addition of Ni and Sb into SAC105, significant improvement in creep resistance of (210%) and (350%) is realized when compared with the SAC105 solder alloy. Likewise, the creep life time of SAC105 alloys was remarkably enhanced (2–3 times) with the minor alloying additions. An analysis of the creep behavior at elevated temperatures suggested that the presence of hard Ni 3 Sn 4 IMC particles and the solid solution hardening effects whi...
... and low cost, which makes them attractive as lead-free solder materials for electronic applic... more ... and low cost, which makes them attractive as lead-free solder materials for electronic applications [1]. However, despite early encouraging results, there is now a wide body of literature confirming that bulk Zn-containing alloys suffer from an inherently poor oxidation resistance ...
Full implementation of the new generation of lead-free solders requires detailed knowledge and un... more Full implementation of the new generation of lead-free solders requires detailed knowledge and understanding of their mechanical behavior. This paper reports on structure, thermal and tensile creep properties of Sn-5 wt.%Sb, Sn-5 wt.%Sb-3.5 wt.%Ag, and Sn-5 wt.%Sb-1.5 wt.%Au lead-free solder alloys. The results show that the microstructure of Sn-5Sb alloy is characterized by the presence of cubed intermetallic compound (IMC) of SbSn particles (<5 m) within -Sn matrix. The two ternary alloys exhibit additional constituent phases of IMCs Ag 3 Sn for Sn-5Sb-3.5Ag and AuSn 4 for Sn-5Sb-1.5Au alloys. Attention has been paid to the role of IMCs on creep behavior. The tensile creep tests were performed within the temperature range 25-130 • C at constant applied stresses. Activation energy (Q) and stress exponent (n) were determined to clarify the deformation mechanism. This study revealed that the solder alloy Sn-5Sb-1.5Au have potential to gave a good combination of higher creep resistance and rupture time, lower melting temperature and higher fusion heat compared with the other two alloys.
ABSTRACT Nowadays, a major concern of Sn–Cu based solder alloys is focused on continuously improv... more ABSTRACT Nowadays, a major concern of Sn–Cu based solder alloys is focused on continuously improving the comprehensive properties of solder joints formed between the solders and substrates. In this study, the influence of Ag and/or In doping on the microstructures and tensile properties of eutectic Sn–0.7Cu lead free solder alloy have been investigated. Also, the effects of temperature and strain rate on the mechanical performance of Sn–0.7Cu, Sn–0.7Cu–2Ag, Sn–0.7Cu–2In and Sn–0.7Cu–2Ag–2In solders were investigated. The tensile tests showed that while the ultimate tensile strength (UTS) and yield stress (YS) increased with increasing strain rate, they decreased with increasing temperature, showing strong strain rate and temperature dependence. The results also revealed that with the addition of Ag and In into Sn–0.7Cu, significant improvement in YS (∼255%) and UTS (∼215%) is realized when compared with the other commercially available Sn–0.7wt. % Cu solder alloys. Furthermore, the Sn–0.7Cu–2Ag–2In solder material developed here also exhibits higher ductility and well-behaved mechanical performance than that of eutectic Sn–0.7Cu commercial solder. Microstructural analysis revealed that the origen of change in mechanical properties is attributed to smaller β-Sn dendrite grain dimensions and formation of new inter-metallic compounds (IMCs) in the ternary and quaternary alloys.
ABSTRACT In this study, the effects of separate and dual additions of small amount of Cu, In and ... more ABSTRACT In this study, the effects of separate and dual additions of small amount of Cu, In and Ag on the microstructure and elastic properties as well as thermal behavior of the eutectic Sn–9Zn solder alloy were investigated. The elastic properties of the newly developed ternary and quaternary alloys have been investigated using sound wave velocity measurements at 4 MHz and T = 25 °C. In particular, the hardness, the attenuation coefficient, the bulk and shear moduli, Young&amp;#39;s and Poisson&amp;#39;s ratio have been established for a range of alloy compositions. Results showed that alloying of Cu, In and Ag resulted in reducing fusion heat, solidus temperature and broadening the pasty range. Moreover, the presence of additional elements in Sn–Zn alloy system allows many complex intermetallic (IMC) phases to form. Both the hardness and reduced modulus increase as the Poisson&amp;#39;s ratio of the alloy decreases. The elastic properties can be correlated with the formation of the new IMC phases. By analyzing the quotient of shear modulus to bulk modulus, we can assume that the Sn–9Zn, Sn–9Zn–1.5Ag and Sn–9Zn–0.7Cu alloys are ductile solders whereas, the Sn–9Zn–1.5In and Sn–9Zn–1.5Ag–0.7Cu alloys are brittle in nature.
Full implementation of the new generation of lead-free solders requires detailed knowledge and un... more Full implementation of the new generation of lead-free solders requires detailed knowledge and understanding of their mechanical behavior. This paper reports on structure, thermal and tensile creep properties of Sn-5 wt.%Sb, Sn-5 wt.%Sb-3.5 wt.%Ag, and Sn-5 wt.%Sb-1.5 wt.%Au lead-free solder alloys. The results show that the microstructure of Sn-5Sb alloy is characterized by the presence of cubed intermetallic compound (IMC) of SbSn particles (<5 m) within -Sn matrix. The two ternary alloys exhibit additional constituent phases of IMCs Ag 3 Sn for Sn-5Sb-3.5Ag and AuSn 4 for Sn-5Sb-1.5Au alloys. Attention has been paid to the role of IMCs on creep behavior. The tensile creep tests were performed within the temperature range 25-130 • C at constant applied stresses. Activation energy (Q) and stress exponent (n) were determined to clarify the deformation mechanism. This study revealed that the solder alloy Sn-5Sb-1.5Au have potential to gave a good combination of higher creep resistance and rupture time, lower melting temperature and higher fusion heat compared with the other two alloys.
The present work is concerned with studying the synthesis and characterization of hybrid aluminum... more The present work is concerned with studying the synthesis and characterization of hybrid aluminum bronze matrix strengthened with nano-aluminum oxide particles (n-Al2O3), and carbon nano tubes (CNTs). The selected matrix composite was successfully incorporated with different weighted percentages of CNTs (i.e. 1.0 and 2.0 wt.%) and/or n-Al2O3 (i.e. 1.0 and 2.0 wt.%) by sintering process. From the microstructure analysis, n- Al2O3 particles was dispersed uniformly and holding over the surface of aluminum bronze. Furthermore, some agglomeration was found due to reinforced CNTs into aluminum bronze matrix. From hardness tests, it was found that incorporated n- Al2O3 and CNTs into matrix increased the hardness of composites to be equal 230 HV, which is around 2.3 times higher than that of an aluminum bronze matrix. Moreover, the wear loss of CNTs - Al2O3/aluminum bronze composites diminished because of the impact of homogeneous circulation of CNTs in aluminum bronze and low corrosion coe...
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Papers by Ahmed Hammad