Microstructure and Mechanical Properties of Similar/Dissimilar Resistance Spot‐Welded Aluminum Alloys for Aerospace Applications

Abstract

2195 aluminum‐lithium (Al‐Li) and 2XXX series aluminum alloys were joined using resistance spot welding (RSW) for the first time. The macrostructure, microstructure, element distribution, microhardness, and tensile‐shear properties of spot welded joints were investigated. The microstructure of the nugget zone of 2195 Al‐Li alloy and 2195, 2219, and 2A14 RSWed joints were fine equiaxed spherical grains. It was found that solute segregation of Cu occurred in the grain boundaries in the nugget zone, forming Al2Cu. The microhardness showed that due to the dissolution of strengthening phase T1, the hardness of the nugget zone of the three types of RSWed joints was smaller than that of the base material. The 2195/2195 joint had the best mechanical performance among the three combinations, with maximum tensile‐shear force and absorbed energy reached 16893.7 N and 24.9 J respectively. The fracture surfaces of all three types of joints exhibited mixed ductile brittle fracture.This article is protected by copyright. All rights reserved.