残余应力场和不同应力比下TC11钛合金的高周疲劳性能  

Property of High Cycle Fatigue of TC11 under Residual Stress and Different Stress Ratios

作　　者：钟丽琼[1,2,3] 严振[3] 梁益龙[3] 姜云[1,3] 徐军[3] 易艳良 

机构地区：[1]贵州大学机械工程学院,贵州贵阳550025 [2]贵阳学院,贵州贵阳550005 [3]贵州省材料结构与强度重点实验室,贵州贵阳550025

出　　处：《稀有金属材料与工程》2015年第5期1224-1228,共5页Rare Metal Materials and Engineering

基　　金：贵州省重点攻关项目(黔科合GZ字[2011]3001)

摘　　要：采用化学腐蚀剥层的方法在X射线应力衍射仪上测定喷丸与未喷丸TC11钛合金表层残余应力场,并测试了此应力场下r=–1,0.1两不同应力比下1×107次的高周疲劳,拟合成疲劳S-N曲线。使用OM、SEM、EDS、超显微硬度仪对材料原始组织、表面形貌、断口形貌、源区成分及疲劳试验后表层硬度变化进行了观察和测定。结果表明,喷丸后在TC11钛合金表层形成一个"钩"形分布的残余压应力场,且层深0.122 mm处压应力值达–463 MPa。此应力场能显著改善其拉/压疲劳性能,而对其拉/拉疲劳性能几乎不起作用。拉/压和拉/拉疲劳试验后,TC11钛合金喷丸试样表层硬度梯度都有降低的趋势,但未喷丸试样却呈上升趋势。A chemical corrosion delamination method was applied to measure the residual stress fields of surfaces in shot-peening（SP） and not shot-peening（NSP） TC11 Ti-based alloys through XRD. Moreover, the 1×107 cycles high-cycle fatigue was tested under r = –1, 0.1 stress ratios in the stress fields, and the S-N curves of fatigue was fitted. OM, SEM, EDS and Ultramicrohardness tester were adopted to investigate the original structure, surface topography, fracture macrograph, micro-area chemical composition, and the variation of surface layer hardness after fatigue test. According to the results of the tests, on the surface of TC11 Ti-based alloy, a residual stress field with‘hook shape＇ distribution forms after shot-peening. The compressive stress value comes up to –463 MPa at the layer depth of 0.122 mm.The stress field improves the property of tension-compression fatigue of TC11 Ti-based alloy, but almost has no effect on the tension-tension fatigue. After the fatigue tests of tension-tension and tension-compression, there is a decreased trend of the surface layer hardness gradient to shot-peening（SP） specimens of TC11 Ti-based alloys, but an increased trend to not shot-peening（NSP） specimens.

关 键 词：残余应力场 应力比 S-N曲线 TC11钛合金 

分 类 号：TG146.23[一般工业技术—材料科学与工程] TG115.57[金属学及工艺—金属材料]