摘要
为了研究蠕变应力作用下的时效热处理对2219铝合金搅拌摩擦焊接头力学性能与微观组织的影响,对蠕变时效与人工时效2种不同热处理工艺板材的搅拌摩擦焊接进行对比实验。研究结果表明:相比于人工时效板材的搅拌摩擦焊(AA+FSW)接头,蠕变时效板材搅拌摩擦焊(CA+FSW)接头的显微硬度、抗拉强度和伸长率均更高;CA+FSW板材和AA+FSW板材在焊缝横截面区的显微硬度呈"W"形分布,且低谷均位于热机影响区;与母材相比,CA+FSW板材和AA+FSW板材接头处的抗拉强度和伸长率都有所降低,其中,CA+FSW板材焊缝抗拉强度平均值为317.8 MPa,为母材的71.9%;AA+FSW板材后焊缝抗拉强度293.8 MPa,为母材的69.1%。板材在焊接过程中基体内的析出相发生了回溶现象,其中CA+FSW板材仍然残留少部分强化相θ′,而AA+FSW板材的析出相则基本全部回溶,因此,焊接后,应力时效板材的显微硬度和抗拉强度更高。
In order to find out the effect of aging heat treatment under creep stress on the mechanical properties and microstructure of 2219 aluminum alloy friction stir welding(FSW)joints,a comparative experimental study on friction stir welding of two different heat treatment processes,creep aging and artificial aging was carried out.The results show that the microhardness,tensile strength and elongation of creep aging sheet friction stir welding joint are higher than those of the friction stir weldingof artificial aging sheet(AA+FSW).The hardness of the two kinds of heat-treated plates in the weld seam area is roughly W-shaped distribution,and the minimum hardness locates in the thermo-mechanically affected zone.The tensile strength and elongation of the welded joint are lower than those of the base material.The average tensile strength of CA+FSW is 317.8 MPa(71.9%of the base material),which is higher than 293.8 MPa in AA+FSW(69.1%of the base material).Microstructure analysis shows that the precipitation phase of the substrats during the welding process has been re-dissolved.Among the CA+FSW plates,a small part of the precipitated phaseθ′remains,but the precipitated phases of the AA+FSW plates are almost completely re-dissolved,which is the reason why the microhardness and tensile strength of the stress aging plate are higher after welding.
作者
焦君
李国鹏
湛利华
杨有良
胡正根
刘观日
JIAO Jun;LI Guopeng;ZHAN Lihua;YANG Youliang;HU Zhenggen;Liu Guanri(China Academy of Launch Vehicle Technology,Beijing 100076,China;College of Mechanical and Electrical Engineering,Central South University,Changsha 410083,China;Beijing Institute of Astronautical Systems Engineering,Beijing 100076,China)
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2021年第2期368-375,共8页
Journal of Central South University:Science and Technology
基金
国家重点研发计划项目(2017YFB0306300)
中南大学创新驱动计划项目(2015CX002)
湖南省科技计划项目(2016RS2015)。
关键词
2219铝合金
蠕变时效
人工时效
搅拌摩擦焊
力学性能
微观组织
2219 aluminum alloy
creep aging
artificial aging
friction stir welding
mechanical properties
microstructure
