Microstructure and mechanical property of Mg-9.8Li-2.9Al-Zn alloy laser welded joint - Details

Author：

Lü, Junxia (Lü, Junxia.) | Yang, Wuxiong (Yang, Wuxiong.) | Wu, Shikai (Wu, Shikai.) | Xiao, Rongshi (Xiao, Rongshi.) (Scholars：肖荣诗)

Indexed by：

EI Scopus PKU CSCD

Abstract：

The　welding　property　of　Mg-9.8Li-2.9Al-Zn　alloy　with　the　thickness　of　2　mm　using　the　CO2　laser　is　investigated.　The　joint　forming,　weld　defects　and　structural　evolution　are　studied　with　optical　microscope　(OM)　and　scanning　electron　microscope　(SEM).　The　mechanical　property　of　the　weldment　is　tested　using　the　microhardness　and　longitudinal　tensile　test　at　room　temperature.　The　result　indicates　that　the　rapid　cooling　during　the　laser　welding　results　in　the　fine　microstructures　with　more　α-Mg　phase　in　the　weld,　compared　with　that　in　the　base　metal.　The　metastable　phase　MgLi2Al　transforms　into　the　stable　phase　AlLi.　The　weld　microhardness　(about　105　HV)　is　bigger　than　that　of　the　base　metal　(about　85　HV).　The　longitudinal　tensile　test　of　the　weldment　shows　the　fractured　location　along　the　base　metal　with　the　reference　yield　strength　of　172　MPa　and　the　percentage　elongation　after　fracture　of　about　24%.

Keyword：

Aluminum alloys Carbon dioxide lasers Welds Lithium alloys Zinc alloys Scanning electron microscopy Mechanical properties Laser beam welding Microhardness Microstructure Tensile testing Ternary alloys Metal testing Magnesium alloys

Author Community：

[ 1 ] [Lü, Junxia]Institute of Laser Engineering, Beijing University of Technology, Beijing 100124, China
[ 2 ] [Yang, Wuxiong]Institute of Laser Engineering, Beijing University of Technology, Beijing 100124, China
[ 3 ] [Wu, Shikai]Institute of Laser Engineering, Beijing University of Technology, Beijing 100124, China
[ 4 ] [Xiao, Rongshi]Institute of Laser Engineering, Beijing University of Technology, Beijing 100124, China