Enhance Mechanical Property and Electrical Conductivity Simultaneously of Sn-Cu-Co Solder Alloys by Directional Solidification

作     者：Fan, Jianglei Wang, Jiaojiao Wang, Xiao Liu, Zhanyun Wu, Shen Wang, Yan Li, Ying Xiangkui, Zhou Wei, Shizhong 

作者机构：Henan Provincial Key Laboratory of Intelligent Manufacturing of Mechanical Equipment Zhengzhou University of Light Industry Zhengzhou China Institute of Mechanical and Electrical Engineering Zhengzhou University of Light Industry Zhengzhou China School of Energy and Power Engineering Zhengzhou University of Light Industry Zhengzhou China Henan Engineering Research Center of Advanced Materials Processing and Testing Zhengzhou University of Light Industry Zhengzhou China Henan University of Science and Technology China 

出 版 物：《SSRN》 

年 卷 期：2023年

核心收录：

主　　题：Tin alloys 

摘      要：Improving mechanical properties of solder alloy can lead to a decrease in its conductivity. The decrease in conductivity of the solder increase the generation of Joule heat and reduce the reliability of the joint. This problem can be solved by adjusting the solidification parameters of solders. In this paper, the effect of the growth rate (V) on the microstructure evolution, microhardness and electrical conductivity of directionally solidified (DS) Sn-0.7Cu-xCo (x=0.5, 1.0, 1.5, 2.0, mass %) alloys was investigated. The Sn-0.7Cu-xCo alloys consists of a Sn-based solid solution (Sn-ss), Cu6Sn5 phase, and CoSn2 phase. The volume fraction of the CoSn2 phase increases with increasing Co content. In the DS specimen, the CoSn2 phases change from block-shaped to a long strip shape with a long axis direction close to the heat flow direction. With increasing V, the growth direction tends to become disordered due to the weakening of the heat flow effect. The microhardness of DS Sn-0.7Cu-xCo alloys is increased with increasing V due to an increase of solution strengthening effect. At the same V, the microhardness of DS Sn-0.7Cu-xCo alloys is increased with increasing Co content. The conductivity of the DS Sn-0.7Cu-xCo alloys is decreased with increasing V. At V ≤ 20 μm/s, the conductivity of the DS Sn-0.7Cu-xCo alloy is even better than that of the as-cast Sn-0.7Cu alloy. The research results provide a new way to improve strength of solder without reducing joint conductivity. © 2023, The Authors. All rights reserved.