Influence of Sn addition on mechanical properties of gas tungsten arc welded AM60 Mg alloy sheets
(1. College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China;
2. National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044, China;
3. Chongqing Academy of Science and Technology, Chongqing 401123, China;
4. Science and Technology on Reactor System Design Technology Laboratory,
Nuclear Power Institute of China, Chengdu 610041, China;
5. College of Materials Science and Engineering, Guilin University of Technology, Guilin 541004, China)
2. National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044, China;
3. Chongqing Academy of Science and Technology, Chongqing 401123, China;
4. Science and Technology on Reactor System Design Technology Laboratory,
Nuclear Power Institute of China, Chengdu 610041, China;
5. College of Materials Science and Engineering, Guilin University of Technology, Guilin 541004, China)
Abstract: The effects of Sn addition on the microstructure and mechanical properties of gas tungsten arc butt-welded Mg-6Al- 0.3Mn (AM60) (mass fraction, %) alloy sheets were investigated by optical microscopy, scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and microhardness and tensile tests. The results indicate that both the average microhardness and joint efficiency of AM60 are improved by the addition of 1% Sn (mass fraction). The ultimate tensile strength of Mg-6Al-1Sn-0.3Mn (ATM610) reaches up to 96.8% of that of base material. Moreover, fracture occurs in the fusion zone of ATM610 instead of in the heat-affected zone of AM60 welded joint. The improvement in the properties is mainly attributed to the formation of Mg2Sn, which effectively obstructs the grain coarsening in the heat-affected zone, resulting in a relatively fine microstructure. The addition of 1% Sn improves the mechanical properties of AM60 welded joint.
Key words: AM60 Mg alloy; ATM610 Mg alloy; gas tungsten arc welding; mechanical properties