搅拌摩擦修复6061-T4铝合金裂纹的组织和性能

Study on microstructure and properties of 6061-T4 aluminum alloy crack repaired by friction stir

采用搅拌摩擦方法对预制裂纹的6061-T4铝合金板进行修复,研究了表面裂纹和贯穿裂纹2种类型试样修复区的微观金相组织和抗拉性能及硬度分布.结果表明:2种预制裂纹试样在合适的焊接工艺参数下,经搅拌摩擦修复后裂纹都能愈合.修复区晶粒由于动态再结晶,晶粒细化形成细小的等轴晶粒,裂纹修复后的试样抗拉强度能达到母材强度的78%,表面裂纹试样的伸长率达到16.1%、贯穿裂纹试样伸长率达到14.2%,为韧性断裂;裂纹修复区的显微硬度的分布曲线基本呈现"W"形.

The pre-cracked 6061-T4 aluminum alloy plate was repaired by friction stir method.The microscopic metallographic structure,tensile properties and hardness distribution of the two types of surface cracks and through-wall cracks were studied.The results show that the two pre-cracked specimens can be healed by friction stir repair under suitable welding parameters.Due to dynamic recrystallization,grain refinement in the repair zone forms fine equiaxed grains.The tensile strength of the sample after crack repair can reach 78%of that of the base metal,and the elongation of the surface crack sample 16.1%,the elongation of the through-crack specimen 14.2%,which is ductile fracture;the distribution curve of microhardness in the crack repairing zone basically shows a"W"shape.