Study on the phase structure of the interface zone of Cu–Al composite plate in cast-rolling state and different heat treatment temperatures based on EBSD

Abstract

The phase structure in the interface zone of Cu–Al composite plate was studied by EBSD after casting and rolling and different heat treatment temperatures. The grain sizes of the matrix and intermetallic compounds in the interface zone were analyzed statistically. The spatial distribution characteristics of the transverse, rolled, normal and various phases were characterized by inverse pole diagram. The results show that with the increase of heat treatment temperature, the phase of the interfacial area of the composite plate is rearranged, the residual stress can be released, and the zero resolution decreases. The interface zone of cast-rolled Cu–Al composite plate is composed of a layer of intermetallic compound, which is Al2Cu; Two layers of intermetallic compounds, both Al, were formed in the interfacial area after heat treatment at 300 °C and 400 °C Al2Cu and Al4Cu9;After heat treatment at 450 °C, the interface region is composed of three layers of intermetallic compounds, which is Al2Cu, AlCu, Al4Cu9;The grain size of copper matrix is obviously larger than that of aluminum matrix. Matrix aluminum, matrix copper, Al2Cu.The average grains of Cu are mostly large Angle grain boundaries, and the orientation difference of adjacent grains in aluminum layer is much smaller than that in copper layer. After heat treatment at 300 °C for 1 h, the recrystallization degree of the interface zone of Cu–Al composite plate is low. After heat treatment at 400 °C for 1 h, the recrystallization in the interfacial zone of Cu–Al composite plate is not complete; After annealing at 450 °C for 1 h, the subgrain boundaries in the aluminum layer grow up, and LAGB is basically converted to HAGB. The distribution characteristics of the characteristic appearance direction in the crystal space of each phase were characterized under the conditions of casting and rolling and different heat treatment temperatures. At the same time, the research results provide theoretical basis and scientific title for optimizing the preparation process and high-end application of Cu–Al composite plate.