ABSTRACT
The hot deformation behavior of Al6061/Nano-Al2O3 composites were investigated at temperatures of 300 to 500 °C and strain rates of 0.001â¼1/s using compression tests. The composite fabricated by the infiltration method consisted of an Al matrix and Al2O3 particles with a mean size of 200 nm. Interestingly, the true stress-true strain curves under all compressive conditions showed a peak stress at the initial stages of deformation, in which the peak stress increased with decreasing temperature and faster strain rate. The Z parameter, which is known as the temperature-compensated strain rate showed a linear relationship with the flow stress. The hot deformation mechanism is believed to occur through dynamic recrystallization, where fine equiaxed grains and dislocations were observed at the deformed specimens. A processing map was applied to evaluate the hot workability and flow instability region to determine the optimal deformation conditions of the composite.
ABSTRACT
The thermal shock reliability and tensile properties of a newly developed quaternary Sn-1.2Ag-0.5Cu-0.4In (wt%) solder alloy were investigated and compared to those of ternary Sn-Ag-Cu based Pb-free solder alloys. It was revealed that the Sn-1.2Ag-0.5Cu-0.4In solder alloy shows better thermal shock reliability compared to the Sn-1.0Ag-0.5Cu and Sn-3.0Ag-0.5Cu solder alloys. The quaternary alloy has higher strength than Sn-1.0Ag-0.5Cu alloy, and higher elongation than Sn-3.0Ag-0.5Cu alloy. It was also revealed that the addition of indium promotes the formation of Ag3(Sn, In) phase in the solder joint during reflow process.
