激光冲击强化对TA15钛合金小孔结构残余应力和疲劳性能的影响  

Effect of Laser Shock Peening on Residual Stress and Fatigue Property of TA15 Titanium Alloy with Hole

作　　者：韩培培[1] 焦清洋 赵栋 孙汝剑 车志刚 HAN Peipei;JIAO Qingyang;ZHAO Dong;SUN Rujian;CHE Zhigang(AVIC Shenya ng Aircraft Corporation,Shenyang 110850,China;AVIC Manufacturing Technology Institute,Beijing 100024,China)

机构地区：[1]航空工业沈阳飞机工业(集团)有限公司,辽宁沈阳110850 [2]中国航空制造技术研究院,北京100024

出　　处：《热加工工艺》2023年第14期76-79,84,共5页Hot Working Technology

摘　　要：采用激光能量30 J、圆形光斑φ4 mm,冲击2次工艺对TA15钛合金小孔结构进行激光冲击强化,研究激光冲击强化对小孔结构残余应力和疲劳性能的影响。结果表明:激光冲击强化后TA15钛合金表面显微硬度最高达402 HV,相对于母材提高了约9%且冲击硬化层深度为0.8 mm;激光冲击强化后在材料表面引入高达-908 MPa的残余压应力,相比于喷丸强化提高了54%;激光冲击强化残余压应力层深度可达1 mm,明显大于喷丸强化残余压应力层深度0.28 mm,较高的残余压应力可以抑制疲劳裂纹的萌生和扩展,而较深的残余压应力层有利于降低裂纹扩展速率,延长裂纹扩展寿命。激光冲击强化可有效提高TA15钛合金小孔结构在385 MPa应力水平下的疲劳寿命,相比于未强化试样的疲劳寿命增益在86%~337%,明显优于喷丸强化后疲劳寿命增益。这是由于残余压应力可降低裂纹扩展的门槛值和裂纹尖端的有效应力强度因子,使疲劳裂纹源从孔内壁转移至试样的上/下表面,同时减小疲劳条带间距。The laser shock peening(LSP)of TA15 titanium alloy samples with hole was carried out with the laser energy of 30 J,circular spot diameter ofφ4 mm and two shock times,and then the effects of laser shock peening on the residual stress and fatigue property of Ti alloy with hole were studied.The results show that the surface microhardness of TA15 titanium alloy by LSP can reach 402 HV,increased by 9%compared with the base material,while the thick of shock peening layer can reach 0.8 mm.The residual compressive stress induced by LSP can reach-908 MPa on the material surface,increased by 54%compared with the base material.The depth of influence layer of residual compressive stress can reach 1mm,which is obviously better than that of the shot peening of 0.28 mm.The higher residual compressive stress can inhibit the initiation and propagation of fatigue crack,and the deeper influence layer of residual compressive stress is beneficial to reduce the crack growth rate and prolong the crack growth life.LSP can effecttively improve the fatigue life of TA15 titanium alloy with fastener hole under 385 MPa stress level,which is increased by 86%to 337%compared with that of the untreated samples and obviously better than that of the shot peening.The residual compressive stress can reduce the threshold value of crack propagation and the effective stress intensity factor at the crack tip,and cause the fatigue source transfer from the hole angle to the sample surface,while decrease the fatigue strip spacing.

关 键 词：激光冲击强化 TA15钛合金 显微硬度 残余压应力 疲劳性能 

分 类 号：TG178.2[金属学及工艺—金属表面处理]