摘要:
采用搅拌摩擦焊接方法对厚度为4 mm的喷射成形7055铝合金板进行焊接试验.分析了焊接速度和旋转频率对接头力学性能的影响,对焊缝的显微组织和断口进行了微观分析.结果表明,当焊接工艺参数选择合适时,可得到外形美观,无缺陷的焊缝.另外焊接接头力学性能与焊接工艺参数存在一定的关系,在旋转频率为1000r/min,且焊接速度为100 mm/min时,可以获得较好的焊接性能,抗拉强度可以达到455MP,断裂形式为韧性和脆性的混合型断裂;焊缝中存在3个组织变化区,其中焊核区内是细小均匀的等轴晶;焊缝显微硬度的最低值出现在前进侧,说明前进侧是焊缝的薄弱环节.
Abstract:
Friction-stir welding was employed in the welding experiment of spray formed 7055 aluminium alloy plate with thickness of 4 mm.The influence of the rotating rate and the welding speed on the mechanical properties of the joint,micro-structure of the weld,and the fracture mode were analyzed.The results showed that good-looking,defectless welds could be obtained with proper welding parameters.The mechanical properties of the joints were related to the welding parameters.When the rotating rate was 1 000 r/min and the welding speed was 100 mm/min,the joints achieved good mechanical properties.The tension strengths of the joints reached 455 MP,and the fracture mode was ductile and brittle mixed.The welds consisted of three zones,among which the weld-nugget zone consisted of fine equiaxed grains.The minimum micro-hardness occurred on the advancing side,which indicated the advancing side is the weakness of the weld.
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