Microstructural and residual stress analysis of functionally graded friction surfaced Al-Cu-Mg-Ag alloy

Abstract

This study analyzed the microstructure and residual stress of a functionally graded friction surfaced Al-Cu-Mg-Ag alloy. To prepare a multilayer material using the friction surfacing process, different layers of Al-Cu-Mg alloy containing 3, 7, and 12 wt% of silver powder were deposited on the Al-Cu-Mg alloy substrate. After homogenization and aging heat treatment, a functionally graded structure with different silver weight percentages in different layers was obtained. The results showed that silver powder reduces the dimensions of the clad layers compared to the sample without silver. After homogenization and artificial aging treatment, a bimodal microstructure formed in the silver-containing sample. It was determined that two types of spherical (S-Al 2 CuMg) and rod-shaped precipitates (Ω precipitates) are formed in the microstructure of different layers. By moving from the first layer to the third layer, the concentration of Ω precipitates increases as the weight percentage of silver added to the microstructure increases. After aging heat treatment, it is observed that the hardness changes are mild, and the average hardness increases from the substrate (134 HV0.1) to the third layer (165 HV0.1).