Microstructure regulation and strengthening mechanism of Al/Ag composites prepared by Plasma Activated Sintered

The objective of this study is to modulate the size of intermetallic compounds to increase the strength of Al–Ag composites. In this study, we prepared Al–Ag composites using plasma-activated sintering (PAS). The effect of the applied current on the nucleation barrier of the Al/Ag alloy phase was investigated. The strengthening mechanism of Ag-reinforced Al matrix composites was explored. We found that two alloy phases, Ag2Al and Ag3Al, were generated in the Al–Ag composites. The alloy phases distributed at the grain boundaries strengthened the Al–Ag composites by enhancing the dislocation density in the matrix and by impeding dislocation motion. The ultimate tensile strength and yield strength of the Al–7Ag composite increased by 60.1% and 166%, respectively, compared with those of pure Al. Moreover, we calculated the contribution of each strengthening mechanism to the overall yield strength. The applied current lowered the nucleation barrier of the alloy phase and facilitated the nucleation process.