Cu/AlN composite and functionally graded materials with high strength and high electrical- and thermal-conductivity fabricated by spark plasma sintering

Abstract In this study, Cu/AlN composites and functionally graded materials (FGMs) were fabricated with the spark plasma sintering method. It was observed that a two-step sintering process, involving sintering under low pressure as the initial stage to remove adsorbed chemicals on the powder, was an effective method for producing sintering objects with high relative density. The hardness of the composites significantly increased with higher volume fraction of aluminum nitride (AlN) particles, while electrical- and thermal-conductivity decreased. Nevertheless, the advanse impact of AlN on thermal-conductivity was found to be minimal. Additionally during compression test, a crack was noted at the interface between Cu and Cu-5 vol%AlN region in two-layered FGMs after, whereas no such crack was observed in the three-layered FGMs. Therefore, it is confirmed that the concept of FGMs is useful in overcoming the shortcomings of mutually exclusiveness among high strength, high electrical- and high thermal-conductively.