银铜侧向复合材料界面结合机理分析

本文采用“包覆锭坯+扩散烧结+冷轧复合”联合工艺制备了银铜侧向复合带材,利用金相显微镜（OM）、扫描电镜（SEM）和能谱仪（EDS）观察分析银铜复合界面结构和元素分布,并分析其银铜复合界面的结合机理。结果表明,银铜复合界面形成过程为：1）银铜接触界面处凹凸不平的表面在轧制力的作用下相互咬合,形成机械结合界面;2）接触面在轧制力的作用下,银铜表面氧化膜破裂,新鲜表面质点间在轧制变形热的作用下产生原子结合;3）在扩散烧结过程中,银铜界面处的原子在高温作用下被激活,银铜原子相互扩散,在界面处发生银铜共晶反应形成液相金属层,随着烧结时间的延长,其共晶反应液相层厚度逐渐增加,随后冷凝结晶,使银铜实现侧向冶金结合。4）在后续中间退火过程中,共晶层与两侧的铜、银基体相互扩散,铜、银原子向更深的方向逐渐扩散,在靠近共晶层铜侧和银侧逐步形成固溶体层,使银与铜的结合强度进一步提高。银铜侧向复合界面结合机理包含机械咬合结合、接触共晶反应自钎焊结合和原子扩散结合3种,复合界面结合强度较好,剪切强度达220 MPa。

Analysis of Interface Bonding Mechanism of Silver-Copper Lateral Composite Prepared by Coated Ingot

In this paper, silver-copper lateral composite strip was prepared by the process of "coated ingot billet diffusion sintering and cold rolling composite". The interfacial bonding strength of silver-copper composite strip was tested by material tensile testing machine.The interfacial structure of silver-copper composite strip was observed by metallographic microscope, scanning electron microscope and energy spectrum, and the structure and bonding mechanism of silver-copper composite strip were analyzed. The results show that the forming process of silver-copper composite interface was as follows: 1) Silver and copper contacted each other under the action of rolling force; 2) The uneven surfaces at the silver-copper contact interface bit each other under the action of rolling force, forming a mechanical bonding interface; 3) Under the action of rolling force, the oxide film on the surface of silver-copper was broken, and atomic bonding occurs between fresh surface particles under the action of rolling deformation heat; 4) In the process of diffusion sintering, the atoms at the silver-copper interface were activated under the action of high temperature, and the silver-copper atoms diffused with each other, so that the silver and copper achieved metallurgical bonding at the connecting surface. The bonding mechanism of the silver-copper lateral composite interface included two kinds of bonding mechanisms: mechanical occlusion bonding and atomic diffusion bonding. The bonding strength of the composite interface was good, and the shear strength of the composite interface was 220 MPa.