Complex Metal Matrix Composites Produced by Powder Metallurgy from Core–Shell Powders

This study investigates the possibility of producing complex metal matrix composites (CMMCs) via powder metallurgy. Two types of powders, a mixture of core–shell Cu@Ag+W@Ag powder and dual core–shell W@(Cu@Ag) powder, have been successfully sintered using spark plasma sintering at 700 °C/5 min, forming Ag–(W+Cu) and Ag–(W@Cu) CMMCs, respectively. Scanning electron microscopy study revealed that both Ag–(W@Cu) and Ag–(W+Cu) CMMCs are characterized by a complex microstructure consisting of Ag matrix reinforced with W@Cu core–shell and a mixture of Cu+W particulates, respectively. The compression tests showed that Ag–(W@Cu) CMMC is characterized by the highest compression yield strength (CYS, 201 MPa) compared to pure Ag (27 MPa) or other counterparts (such as Ag–W, Ag–Cu). On the other hand, Ag–(W+Cu) CMMC exhibits a lower CYS value (150 MPa) by approximately 25% compared to Ag–(W@Cu) CMMC; while its tensile yield strength (TYS) reaches 99 MPa, which is 98% higher than the TYS of pure Ag (50 MPa).