摘要
The effects of Al content and Ca/Al mass ratio on the microstructure and mechanical properties of tungsten inert gas(TIG)welded Mg-2Ca-x Al-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 Mg_(2)Ca to(Mg,Al)_(2)Ca with the decrease of Ca/Al ratio,and the(Mg,Al)_(2)Ca could be further transformed to Al_(2)Ca under welding thermal cycle.Furthermore,dynamic dissolution and precipitation of Laves phases and Al_(8)Mn_(5)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
financially supported by the National Natural Science Foundation of China(No.52175288)
the Scientific and Technological Research Program of Chongqing Municipal Education Commission(Nos.KJQN202001527 and KJZD-K202001502)
the Innovation Research Group of Nniversities in Chongqing(No.CXQT21030),t Chongqing Talent Project(No.CQYC201905100)
the State Key Lab of Advanced Welding and Joining,Harbin Institute of Technology(No.AWJ-22M21)
the Natural Science Foundation of Chongqing(No.cstc2020jcyj-msxm X0552)。
