表面超声滚压及渗氧复合强化对纯钛断裂韧性的影响  

Effects of ultrasonic surface rolling process and combined oxygen boost diffusion treatment on fracture toughness of pure titanium

作　　者：魏琦 贾云飞 杨晓峰 李晓 张显程[1] WEI Qi;JIA Yunfei;YANG Xiaofeng;LI Xiao;ZHANG Xiancheng(School of Mechanical and Power Engineering,East China University of Science and Technology,Shanghai 200237,China)

机构地区：[1]华东理工大学机械与动力工程学院,上海200237

出　　处：《压力容器》2022年第5期16-25,共10页Pressure Vessel Technology

基　　金：国家自然科学基金项目(51975211);上海市青年科技启明星项目(20QA1402500)。

摘　　要：通过表面超声滚压处理、渗氧处理以及复合处理对工业纯钛进行不同方式的表面强化,研究不同表面强化处理对纯钛微观组织、力学性能的改变以及对断裂韧性J;的影响。结果表明,表面强化对纯钛断裂韧性J;的作用受晶粒长大以及表面改性两个因素的影响:渗氧处理和复合处理过程中的真空热处理会导致晶粒长大,是断裂韧性提升的有利因素;而超声滚压处理、渗氧处理以及复合处理所形成的表面强化层则会对断裂韧性产生不利影响,这是由于这些表面强化层会降低裂纹扩展初期裂纹尖端的塑性区尺寸,从而导致裂纹扩展的J阻力降低,材料抗断裂性能下降。Ultrasonic surface rolling process(USRP),oxygen boost diffusion(OBD) and their combination(USRP-OBD) were used to strengthen the surface of pure titanium.The effects of different surface strengthening methods on the microstructure, mechanical properties and fracture toughness J;were studied.The results show that the effect of surface strengthening on the fracture toughness J;of pure titanium is affected by two factors: grain growth and surface modification.The vacuum heat treatment during the OBD treatment and the USRP-OBD treatment cause grain growth, which is a favorable factor for improving fracture toughness.Whereas the surface strengthened layers formed by USRP,OBD treatment and USRP-OBD treatment have an adverse effect on the fracture toughness, because these surface strengthened layers will decrease the size of the plastic zone at the crack tip at the initial stage of crack propagation, resulting in the decrease of J resistance of crack propagation, and decrease of the fracture resistance of the material.

关 键 词：表面强化 纯钛 超声滚压 渗氧 断裂韧性 

分 类 号：TH142.3[一般工业技术—材料科学与工程] TG174.4[机械工程—机械制造及自动化] O346.1[金属学及工艺—金属表面处理]