激光冲击强化提高外物打伤TC4钛合金疲劳强度的试验研究

发布时间：2018-03-08 18:37

本文选题：激光技术　切入点：疲劳强度　出处：《中国激光》2016年07期 　论文类型：期刊论文

【摘要】：采用激光冲击强化(LSP)技术对TC4钛合金试件进行表面处理,利用空气炮试验系统对试件边缘进行外物冲击模拟,对外物打伤(FOD)试件进行拉-拉疲劳试验。结果表明,激光冲击强化有效提高了外物打伤TC4钛合金试件的疲劳强度;未强化试件疲劳裂纹源萌生在缺口根部靠近上表面的位置,强化试件的裂纹源萌生位置在材料内部,与缺口根部有一段距离,且裂纹萌生难度增大。数值应力分析结果表明,强化后试件凹坑的最大拉应力值为668.90 MPa,比强化前的1076.21 MPa减小了37.85%;强化后试件凹坑中心的残余拉应力比强化前平均减小了350 MPa;加载拉应力后,强化前后试件凹坑最大应力分别增大到1542.36 MPa和1124.37 MPa,强化后比强化前试件应力减小了30.22%,说明压应力对裂纹的萌生有明显的延缓作用。残余压应力的引入是激光冲击强化提高打伤试件疲劳强度的主要原因之一。
[Abstract]:The surface of TC4 titanium alloy specimen was treated by laser shock hardening (LSP) technique. The external impact was simulated by the air gun test system, and the tensile fatigue test was carried out on the specimen with external material injury. The fatigue strength of TC4 titanium alloy specimen injured by external material was effectively improved by laser shock strengthening, the fatigue crack source of unstrengthened specimen was located near the upper surface of the notch root, and the crack initiation position of the strengthened specimen was inside the material. There is a distance from the root of the notch and the difficulty of crack initiation increases. The numerical stress analysis results show that, The maximum tensile stress of the pit is 668.90 MPa, which is 37.85 MPa lower than that of 1076.21 MPa before strengthening, and the residual tensile stress in the center of the pit decreases by 350MPa on average after strengthening. The maximum stress of the pit increased to 1542.36 MPa and 1124.37 MPa, respectively, and the stress of the specimen decreased 30.22 2 after strengthening, indicating that the compressive stress has a significant effect on the crack initiation. The introduction of residual compressive stress is laser shock. One of the main reasons for strengthening the fatigue strength of injured specimens.
【作者单位】：空军工程大学等离子体动力学重点实验室;中国人民解放军第5702工厂;
【基金】：国家重点研究发展计划(2015CB04700) 国家自然科学基金(51205406,51505496)
【分类号】：V261.8

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