摘要
目前,有关超声冲击法对工业纯钛焊接接头疲劳性能改善效果的影响研究报道不多。采用超声冲击处理方法对工业纯钛TA2焊接接头进行全覆盖强化处理,通过疲劳对比试验分析了不同超声冲击处理时间对TA2焊接接头疲劳性能的影响;通过接头微观组织、断口形貌观察分析了超声冲击处理提高TA2焊接接头抗疲劳断裂性能的微观机理。结果表明,在200 MPa应力条件下,原始焊态试样平均历经11 645次循环就已断裂,经超声冲击处理3 min的焊接试样平均历经23 424次循环后才断裂,疲劳寿命提高约1倍;在超声冲击过程中,试样表层受到大的应变量、高应变速率和重复载荷的作用,使得形变孪晶不断增加;重复载荷的作用,可以再次在内部产生更加细小的孪晶,孪晶与孪晶间重复交割导致晶粒进一步细化。
TA2 pure titanium welded joints were fully coverage-strengthened by ultrasonic impact treatment( UIT),and the influences of different processing time of UIT on fatigue properties of TA2 welded joints were analyzed by fatigue comparative test. Subsequently,the fatigue fracture mechanisms of the anti-fatigue performance of TA2 welded joint treated by UIT were studied by microstructure of joint and morphology of fracture surface. Results showed that under a pressure of 200 MPa,the original welding specimens got fractured after 11 645 cycles,while the welding specimens treated by UIT for 3 min got fractured after 23 424 cycles,which indicated that fatigue lifetime increased by 1 time. In addition,during the process of UIT,the specimen surface was affected by large dependent variable,high strain rate and repeated load,which caused the constantly increased deformation twins. Under the repeated load,the tinier twin crystals were formed,and crystal particle became more refined further due to repeated interlacement between different twin crystals.
出处
《材料保护》
CAS
CSCD
北大核心
2015年第12期53-56,8,共4页
Materials Protection
关键词
焊接接头
疲劳性能
超声冲击
纯钛材
welded joints
fatigue properties
ultrasonic impact treatment
TA2
作者简介
[通信作者]李进一（1988-），从事压力容器技术工作，电话：15951289958，E—mail：lijinyi880312@163．cam
