2024铝合金搅拌摩擦焊接头塑性变形行为研究

摘要

To explore the mechanical properties and the plastic deformation behavior of the friction stir welding brazed tube,the microstructures and mechanical properties of the 5 mm thick 2024-O aluminum alloy friction stir welded（FSW） joints were investigated.Emphasis was placed on the effect of the microstructure heterogeneity on the global and local tensile properties of FSW joints.The relationship between microstructures and mechanical properties of FSW joints were studied.The results show that the tensile properties of the joint are very heterogeneous leading to lower ductility.The middle zone of the BM is the weakest region where the strain localizes early and reaches 23% during the tensile test.However,the local strain of the weld nugget zone and the base material are 3% and 11% respectively.The highly inhomogeneous deformation throughout the joint caused by heterogeneous microstructure is the reason for the 44% decrease in elongation of the as-welded joint compared with that of the BM.%为了研究搅拌摩擦焊卷焊管坯的力学性能及接头塑性变形行为,以5 mm厚的2024退火态铝合金搅拌摩擦焊板坯为对象,采用网格法测试接头塑性变形分布,用EBSD测量接头各区域晶粒尺寸及位相,并结合SEM观察接头第二相的分布,研究了接头力学性能、应变分布与微观组织之间的关系.研究表明：搅拌摩擦接头强度与母材等强,延伸率下降44%;接头前进侧距离焊缝中心8～17 mm的母材较早出现了应变的集中,局部应变可达23%,而焊核区和接头返回侧母材发生的变形较小,平均应变分别为3%和11%,各区域应变的不均匀主要是由于接头各