An Innovative Strategy for Achieving Interface Gradient Material Using Co-Deposition Technology

In this study, high-performance SiC whisker (SiCw)-reinforced Cu matrix functionally graded materials (FGMs) were achieved through the synergy of numerical simulation and co-electrodeposition and then successfully applied as the interface of Cu and Si. A comprehensive numerical simulation framework was developed to investigate the influence of gradient transition modes and the maximum volume fraction of SiCw on the thermal-mechanical properties in the different gradient structures. The optimized FGMs via numerical simulation were fabricated using a co-electrodeposition technique, producing a 100 μm thick coating with a SiCw volume fraction gradient ranging from 0% to 40%. The interface of Cu and SiC was void free in the FGMs and the SiCw was coated by nano-scale Cu grains during the electroplating process. The coefficient of thermal expansion in FGMs was higher than 9.78 × 10^-6 K^-1, which was the coefficient of thermal expansion in the Cu-40% vol. SiCw, and lower than 16.4 × 10^-6 K^-1, which was the coefficient of thermal expansion in pure Cu. Notably, the bonding interface area between the Cu/Si joint with the gradient-structured FGMs was more than twice that of non-graded materials. The enhanced thermal-mechanical performance was attributed to the synergistic effects of the nano-scale grain-reinforced SiCw-Cu interface and an optimized stress distribution achieved by the gradient structure.