Cu／Al双辊异温铸轧复合界面局部熔合机理

摘要

以传统双辊铸轧工艺为基础，采用金属熔体触辊凝固制备Cu、Al带坯并轧制复合，利用高温Cu带与Al带强压接触传热及其产生的Al带表面浅层熔化现象，提出一种基于界面“局部熔合”的Cu／Al双辊异温铸轧复合工艺。利用非线性热－力耦合有限元方法，数值模拟分析了Cu带和Al带初始温度Tc和Ta、层厚比K、压下率ε对Cu／Al复合界面接触换热与温度分布的影响规律，给出了实现界面“局部熔合”的工艺条件。在自制的物理模拟装置上进行Cu／Al异温压力复合实验，并通过界面的SEM、EDS分析，验证了Cu／Al界面“局部熔合”的工艺条件，揭示了Cu⁃Al二元合金反应扩散是“局部熔合”作用下Cu／Al界面冶金结合的主要机制。%Baded on the traditional twin⁃roll casting and rolling process, we propose a new technology to fabricate Cu/Al layered strips based on local fusion of the contact bonding interface. First, component strips of Cu and Al were produced by pouring liquid metal onto the roller surface, and then feeding them both into the roll bite. We found a melting phenomenon on the skin layer of the Al strip, caused by heat conduction between the Cu and Al strips at high temperature and contact pressure in the rolling deformation zone. Through a numerical simulation u⁃sing the nonlinear thermal⁃mechanical coupled finite element method, we investigate the influence of the initial tem⁃perature of the Cu and Al strips Tc , Ta , the thickness ratios K, the reduction ε on the contact heat transfer, and the distribution of the bonding interface temperature, and present the process conditions necessary for achieving lo⁃cal fusion at the bonding interface. We also design a special physical simulation device to conduct the Cu/Al bond⁃ing experiment under different temperatures and contact pressures. The scanning electron microscopy ( SEM) and energy dispersive spectroscopy ( EDS) analysis results of the bonding interface show that Cu⁃Al binary alloy reaction diffusion is the main mechanism of the Cu/Al interface metallurgical bonding under the effect of local fusion. Hence, we have verified the process conditions necessary for local fusion of the Cu/Al bonding interface.