线能量对AZ31B变形镁合金GTAW焊接接头沉淀相的影响

Effect of Line Energy on Precipitates in GTAW Welded Joints of AZ31B Magnesium Alloy

对2.2mm厚挤压态镁合金AZ31B板材进行交流GTAW焊研究,线能量分别取45.5、52、58.5、和65J/mm。结果表明:随着线能量的增加,焊缝熔化宽度逐渐增加,线能量为65J/mm时,表面成形最佳,焊缝达到熔透状态;焊缝区沉淀相β-Mg17Al12的平均尺寸及所占面积百分比随焊接线能量的增大而增大,当焊接线能量从45.5J/mm增大至65J/mm时,β-MMg17Al12的平均尺寸从1μm增大为4μm,在焊缝区所占面积百分比由8%增大至30%。

In this study,AZ31B alloy with 2.2 mm thickness was welded by GTAW process.The welding line energy was 45.5 J·mm^-1,52 J·mm^-1,58.5 J·mm^-1 and 65 J·mm^-1,respectively.The results show that：the width of welding fusion increased with the welding line energy increase.The best weld surface and penetration were obtained when the welding current was 65 J·mm^-1.The average size of precipitates β-MMg17Al12 in weld zone and percentage share of area increased with the increasing of heat input.When the welding heat input increased from the 45.5 J·mm-1 to 65 J·mm-1,the average size of β-MMg17Al12 increased from 1 micron to 4microns,percentage share area in the welding seam zone increased from 8% to 30%.