Abstract
The effects of Al content and Ca/Al mass ratio on the microstructure and mechanical properties of tung-sten inert gas(TIG)welded Mg-2Ca-xAl-0.5Mn(x=0,1,5)alloy joints were studied in present work.Results showed that increasing Al content was effective in reducing the dendrite spacing at the fusion zone(FZ)edge.The Laves phases in the FZ and the heat-affected zone(HAZ)can be changed from Mg2Ca to(Mg,Al)2Ca with the decrease of Ca/Al ratio,and the(Mg,Al)2Ca could be further transformed to Al2Ca under welding thermal cycle.Furthermore,dynamic dissolution and precipitation of Laves phases and Al8Mn5 phases occurred in the HAZ,resulting in a gradient microstructure and hardness peak in this area.The tensile properties of the joints were significantly improved with the increase of Al content,which was mainly due to the modification of Laves phases.
基金项目
国家自然科学基金(52175288)
Scientific and Technological Research Program of Chongqing Municipal Educa-tion Commission(KJQN202001527)
Scientific and Technological Research Program of Chongqing Municipal Educa-tion Commission(KJZD-K202001502)
Innovation Research Group of Nniversities in Chongqing(CXQT21030)
Chongqing Talent Project(CQYC201905100)
State Key Lab of Advanced Welding and Joining,Harbin Institute of Technology(AWJ-22M21)
重庆市自然科学基金(cstc2020jcyj-msxmX0552)