Grain growth and its effect on mechanical properties of 1060 aluminum alloy laser welded joints

1060铝合金激光焊晶粒生长情况及其对接头力学性能的影响 Grain growth and its effect on mechanical properties of 1060 aluminum alloy laser welded joints 高启涵 GAO Qihan 1 first-author 金成 JIN Cheng 1 大连交通大学材料科学与工程学院 大连交通大学材料科学与工程学院 School of Materials Science and Engineering,Dalian Jiaotong University School of Materials Science and Engineering,Dalian Jiaotong University 采用宏观数值模拟与微观EBSD试验相结合的方法研究了激光焊焊接1060铝合金焊缝晶粒的生长情况及其对接头力学性能的影响。结果表明:晶粒尺寸随着热输入的降低而减小,焊缝中心逐渐产生致密的等轴晶,增强晶界强化作用,从而提升焊缝区塑性;在热输入降低过程中,熔池形状从椭圆状过渡为泪滴状,柱状晶生长形态受其影响由弯曲转变为竖直,柱状晶的生长方向与热流分布一致,垂直于熔化边界尾部,并且随着热输入降低与焊缝中心线夹角增大。柱状晶各向异性的特点使其与拉伸力趋近平行时抗拉强度更高;在较小热输入下焊缝晶粒会产生较为明显的立方织构,有助于提升焊缝区塑性;热输入由120 J/mm降至75 J/mm,接头拉伸强度逐步提升,而当热输入降至58 J/mm时焊接速度过快,会产生明显的气孔缺陷,使接头抗拉强度与75 J/mm时相比有所下降。 From the perspective of the combination of macroscopic numerical simulation and microscopic EBSD experiment,the weld grain growth and its effect on the mechanical properties of the laser welding joint for 1060 aluminum alloy are studied. The results show that the grain size reduces as the heat input decreases,and dense equiaxed crystals gradually generates in the center of the weld,which will enhance grain boundary strengthening effect and the plasticity of the weld metal zone;in the process of heat input reduction,the shape of the molten pool transitions from elliptical shape to teardrop shape. The growth shape of the columnar crystal changes from bending to vertical under the influence of the columnar crystal. The growth direction of columnar crystals is consistent with the heat flow distribution and perpendicular to the end of fusion boundary,and the angle between the growth direction of columnar crystals and the weld center line increases as the heat input decreases. The characteristic of columnar crystal anisotropy makes its tensile strength higher when it is close to the tensile force;with small heat input,the weld grain will produce a obvious cubic texture,which helps to improve the plasticity of the weld metal zone;the tensile strength of the joint gradually increases when the heat input reduces from 120 J/mm to 75 J/mm,and when the heat input reduces to 58 J/mm,the welding speed is too fast,which will produce obvious pore defects,and the tensile strength of joint declines comparing with that when heat input is 75 J/mm. 1060铝合金 焊接热输入 晶粒生长 力学性能 数值模拟 1060 aluminum alloy welding heat input grain growth mechanical properties numerical simulation TG457.14 2022-03-08 7 50