摘要
针对TC6钛合金进行了激光冲击强化(LSP)参数设计,应用XRD衍射仪对LSP试件进行了残余应力分布规律测试和图谱分析,采用透射电子显微镜对强化层微观组织进行了观察,对有无LSP标准振动疲劳试件进行了振动疲劳对比试验。研究表明,TC6钛合金LSP较佳功率密度为3 GW/cm2,LSP能在材料表层产生深度为1.6 mm的高数值残余压应力场,表面残余应力可达-660 MPa,深度为0.1 mm处残余应力最大,最大值可达-690 MPa;LSP后没有新相产生,且晶粒细化、残余微观应变导致Bragg衍射峰宽化;LSP后钛合金表层出现高密度位错和纳米晶;钛合金标准振动疲劳试件LSP后疲劳极限由438.6 MPa增加至526.7 MPa,提高20.1%;疲劳断口分析表明LSP产生的组织细化和高数值残余压应力场可以有效抑制疲劳裂纹的萌生和扩展,从而提升TC6钛合金的抗疲劳性能。
Laser shock peening （LSP） of TC6 titanium alloy was designed and the characteristics of the residual stress distribution with different power density were tested by XRD. The microstructure after LSP was observed by transmission electron microscope （TEM）. And then, vibration fatigue test was carried out on TC6 samples with and without LSE Results show that the optimal power density to process TC6 titanium alloy is 3 GW/cm2. LSP could induce high residual compressive stress field in material, and the residual stress on surface could reach -660 MPa. The maximum residual stress is -690 MPa, locating at 0.1 mm below the surface. There is no new phase produced by LSP. The grain refinement and the permanent micro-deformation make the width of Bragg diffraction peak broad. High density dislocation and nanocrytallization are produced after LSP, and the nanocrystal sizes range from several nanometers to dozens of nanometers. LSP improves the endurance fatigue limit of TC6 sample from 438.6 MPa to 526.7 MPa, about 20.1% higher than the endurance limit before LSP. Typical fracture appearance indicates that residual stress and microstructure refinement by LSP together enhance the fatigue ability of TC6 titanium alloy.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2013年第8期1643-1648,共6页
Rare Metal Materials and Engineering
基金
国家自然科学基金项目(51205406)
