130mm铝合金扫描激光填丝焊接头微区组织和性能

针对船用130 mm 5A06铝合金厚壁结构件的扫描激光填丝焊接头，对其焊缝（weld metal，WM）、热影响区（heat affected zone，HAZ）及母材（base metal，BM）的显微组织进行研究，并通过维氏硬度和微型剪切试验研究了接头各区力学性能差异.结果表明，5A06铝合金单激光焊缝以等轴晶为主，填丝焊焊缝以柱状晶为主，HAZ和BM晶粒比WM粗，母材及热影响区为轧制的纤维状组织；由于焊接热循环作用，接头热影响区硬度略高于母材，抗剪强度二者差别不大，单激光焊缝硬度和抗剪强度略高于填丝层.总体而言，焊缝区强度低塑性好，母材及热影响区强度高塑性低.

Micro-area organization and performance of 130 mm Al alloy scanning laser filler wire welded joint

The microstructure of the weld metal (WM), heat affected zone (HAZ) and base metal (BM) was studied and tested for the 130 mm thick scanning laser filler wire welded joint of marine 5A06 aluminum alloy rear wall structure members. Vickers hardness and micro-shear test were used to study the difference in mechanical properties of the joints. The results reveal that the single laser welding seam of 5A06 aluminum alloy is dominated by equiaxed crystals, the filler welds are mainly columnar crystals, the HAZ and BM grains are thicker than WM with rolled fibrous structures. Due to the thermal cycle of welding, the hardness of HAZ is slightly higher than BM, and the shear strength is not much different. The hardness and shear strength of the single laser weld are slightly higher than the filler layer, and the overall weld zone strength is low. On the whole, the BM and HAZ have higher shearing strength, while the plasticity is lower.