Structure and growth behavior of intermediate phase in Cu–Zr diffusion couple heated by pulse current

Abstract

In this research, Cu–Zr diffusion couples were heated by pulse current and a conventional heating method, respectively. Comparative analyses on the diffusion behavior of Zr and Cu atoms, interfacial structure and growth behavior of diffusion reaction area were carried out. The results show that applying pulse current can accelerate the migration rate of atoms, promote the diffusion of Zr atoms to the copper substrate in a short holding time, achieve a metallurgical bonding and form a continuous, dense reaction layered structure with a two-layer interface. The pulse current heating can induce the formation of lamellar ZrCu phase in the copper substrate interface. After holding for a relatively short period of time, a large number of Zr atoms crossed through the ZrCu phase, formed ZrCu3 phase in the copper rich phase side and grew gradually along the depth direction of copper substrate. Meanwhile, the growth rate of ZrCu phase was relatively slow due to the weak diffusion ability of Cu atom to in zirconium matrix.