Most conductive wires in homes and vehicles are made of pure copper, but copper conductors in electrical circuits are subject to the “skin effect” and copper is relatively expensive and heavy. Cu-Al composites have shown great potential for application in the field of conductors due to their simultaneous high electrical conductivity, high thermal conductivity, and low contact resistance of copper as well as the light mass and corrosion resistance of aluminum, and have attracted much attention in recent years.

The interface of Cu-Al composites generates a variety of intermetallic compounds (IMCs) at temperatures higher than 120°C. The interdiffusion coefficients of Cu and Al in each IMC are different, which leads to different growth rates of each IMC layer. The width of the diffusion layer is not only related to the diffusion time but also to the number of IMC layers. These brittle IMCs seriously affect the mechanical and electrical properties of Cu-Al materials. Therefore, it is of great scientific and technical importance to deeply investigate the evolution of microstructure and understand the significant changes in Cu-Al interfacial composition and the growth behavior of IMCs.

In this paper, Cu-Al diffusion couples were prepared to study the diffusion process, microstructure and growth kinetics of IMCs in Cu-Al interface at 600°C-800°C, and the mechanical and electrical properties of Cu-Al diffusion couples were evaluated. This study provides a reasonable explanation for the formation of Cu-Al intermediate phase at 600°C-800°C and offers reliable data support for the determination of the electrical and mechanical properties of Cu-Al composites. The relevant research results were published in the international journal «Intermetallics» (JCR Q1, IF=4.4) with the title “The growth behavior and kinetics of intermetallic compounds in Cu-Al interface at 600°C-800°C”.

Fig. 1. BSE-SEM images of interfacial layers of Cu-Al after annealing at different temperatures for 20 min: (a) 600°C, (b) 700°C, (c) 800°C and EPMA line scan results: (d) 600°C, (e) 700°C, (f) 800°C

Fig. 2. Diffusion fitting curves: (a) time, (b) temperature

Fig. 3. Diagram of the formation and evolution mechanism of the interfacial layer

Title: The growth behavior and kinetics of intermetallic compounds in Cu-Al interface at 600°C-800°C

Authors: Dandan Zhao, Weijia Guo, Zhichao Shang, Chengyi Xu, Xinran Gao, Xiaohong Wang*

Link: https://www.sciencedirect.com/science/article/pii/S0966979524000633

DOI: https://doi.org/10.1016/j.intermet.2024.108244

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