Interfacial characteristics and mechanical properties of additive manufacturing martensite stainless steel on the Cu-Cr alloy substrate by directed energy deposition

作     者：Wenqi Zhang Hailong Liao Zhiheng Hu Shasha Zhang Baijin Chen Huanqing Yang Yun Wang Haihong Zhu Wenqi Zhang;Hailong Liao;Zhiheng Hu;Shasha Zhang;Baijin Chen;Huanqing Yang;Yun Wang;Haihong Zhu

作者机构：Wuhan National Laboratory for OptoelectronicsHuazhong University of Science and TechnologyWuhan 430074China State Key Laboratory of Material Processing and Die&Mould TechnologySchool of Material Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China XI’AN Space Engine Company LimitedXi’an710100China 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2021年第90卷第31期

页      面：121-132页

核心收录：

学科分类：08[工学] 0806[工学-冶金工程] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：supported by the Human Spaceflight Program of China(D050302) the Military Industry Stability Support project(2019KGW.YY4007Tm)。 

主　　题：Directed energy deposition Additive manufacturing Bimetal Interfacial characteristics Crack 

摘      要：Copper/steel is a typical bimetal functional material,combining the excellent electrical and thermal conductivity of copper alloy and the high strength and hardness of stainless steel.There has been recent interest in manufacturing copper/steel bimetal by directed energy deposition(DED)due to its layer-bylayer method.However,cracks tend to form on the copper/steel interface because of the great difference in thermal expansion coefficient and crystal structure between copper and steel.In this work,interfacial characteristics and mechanical properties of the copper/steel bimetal were studied from one layer to multilayers.The laser power has a great influence on the Cu element distribution of the molten pool,affecting the crack formation dramatically on the solidification stage.Cracks tend to form along columnar grain boundaries because of the Cu-rich liquid films and spherical particles in the cracks.Crack-free and good metallurgical bonding copper/steel interface is formed at a scanning velocity of 800 mm/min and the laser power of 3000 W.The ultimate tensile strength(UTS)and the break elongation(EL)of the vertically combined crack-free copper/steel bimetal are 238.2±4.4 MPa and 20.6±0.7%,respectively.The fracture occurs on the copper side instead of the copper/steel interface,indicating that the bonding strength is higher than that of the Cu-Cr alloy.The UTS of the horizontally combined crack-free copper/steel bimetal is 746.7±22.6 MPa,which is 200%higher than that of the Cu-Cr alloy substrate.The microhardness is 398.6±5.4 HV at the steel side and is 235.3±64.1 HV at the interface,which is400%higher than that of the Cu-Cr alloy substrate.This paper advances the understanding of the interfacial characteristics of heterogeneous materials and provides guidance and reference for the fabrication of multi-material components by DED.