激光冲击强化TC4双相钛合金过程中β相的细化机理  

Refinement Mechanism ofβPhase During Laser Shock Peening of TC4 Duplex Titanium Alloy

作　　者：纪飞飞 JI Feifei(Suzhou Chien-shiung Institute of Technology,Suzhou 215411,China;School of Mechanical Engineering,Jiangsu University,Zhenjiang 212013,China)

机构地区：[1]苏州健雄职业技术学院,苏州215411 [2]江苏大学机械工程学院,镇江212013

出　　处：《机械工程材料》2022年第1期41-46,共6页Materials For Mechanical Engineering

基　　金：校青年自然科学基金资助项目(2019QNZK008);太仓市基础研究计划(面上)项目(TC2020JC13);浙江省基础公益研究计划项目(LGF18E090001)。

摘　　要：采用激光冲击强化(LSP)技术对TC4双相钛合金进行表面强化处理(冲击0~3次),研究了β相晶粒细化机理以及强化前后残余应力、表面硬度及疲劳强度的变化。结果表明:激光冲击强化过程中,β相晶粒内的位错首先通过滑移形成位错线,随着塑性变形加剧,位错不断堆积形成位错壁和位错胞,位错进一步运动后形成亚晶界,并通过动态再结晶实现晶粒细化;3次冲击强化后,合金的晶粒尺寸由原始板材的21.33μm降至4.68μm;随着激光冲击强化次数增加,合金表面的残余压应力、显微硬度及疲劳强度均增大。Laser shock peening(LSP)technology was used to strengthen the surface of TC4 duplex titanium alloy(impact 0-3 times).The grain refinement mechanism ofβphase and the changes of residual stress,surface hardness and fatigue strength before and after strengthening were studied.The results show that during the process of LSP,dislocations in theβphase grains firstly formed dislocation lines by slipping.As the plastic deformation intensified,dislocations piled up continuously to form dislocation walls and dislocation cells.After further movement of dislocations,sub grain boundaries were formed,and the grain refinement was achieved through dynamic recrystallization.After three times of impact strengthening,the grain size of the alloy was reduced from 21.33μm of the original sheet to 4.68μm.As the time of LSP increased,the residual compressive stress,microhardness and fatigue strength of the alloy surface increased.

关 键 词：双相钛合金 激光冲击强化 Β相 位错滑移 晶粒细化 

分 类 号：TG39[金属学及工艺—金属压力加工]