Microstructure and mechanical properties of joint of MGH956 alloy in TIG welding
1.School of Material Science and Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China; 2.Jiangsu Province Key
Laboratory of Highend Structural Materials, Zhenjiang, Jiangsu 212013, China; 3.Electrical and Mechanical Services
Department of Wuxi Institute of Arts and Technology, Wuxi, Jiangsu 214000, China
Abstract：Tungsten insert gas(TIG) weldings of MGH956 alloy plates with 1.3 mm thickness were conducted with base metal(BM) and self-made high Ni wire as fill materials, respectively. The two kinds of joint microstructures and mechanical properties were compared and analyzed.With high Ni wire as fill material in the process of welding, grain refinement is realized in weld joint with reduced holes, and new composite reinforced phase by TiC is produced in the joint to ensure the joint quality and to reduce the agglomerate of nano-scale reinforced Al-Y-O composite oxide particles. The mechanical testing results show that tensile strength of the sample welded by BM welding is only 57％ of that of BM with softening at weld metal(WM). Hardening appears at WM for filling high Ni wire, and the tensile strength of 581 MPa reaches about 80.7% of that of BM. The two cases of heat affected zone hardness are equal to that of BM, and the fracture surface of two weld joints both exhibit brittle fracture.
2014, Vol. 35 
