激光冲击强化对TA15钛合金双孔结构显微组织和疲劳性能的影响  

Effect of laser shock peening on microstructure and fatigue property of TA15 titanium alloy with double holes

作　　者：韩培培[1] 臧旭 董志 李世键[1] 焦清洋 邓希光 Han Peipei;Zang Xu;Dong Zhi;Li Shijian;Jiao Qingyang;Deng Xiguang(AVIC Shenyang Aircraft Corporation,Shenyang Liaoning 110850,China;The First Military Representative Office of Air Equipment in Shenyang,Shenyang Liaoning 110850,China;School of Materials Science and Engineering,Shenyang Aerospace University,Shenyang Liaoning 110136,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]空装驻沈阳地区第一军事代表室,辽宁沈阳110850 [3]沈阳航空航天大学材料科学与工程学院,辽宁沈阳110136

出　　处：《金属热处理》2023年第7期254-258,共5页Heat Treatment of Metals

摘　　要：对TA15钛合金进行激光冲击强化,研究了激光冲击强化对双孔结构试样显微组织、残余应力和疲劳性能的影响。结果表明,经激光能量25 J、圆形光斑?4 mm,冲击2次的激光冲击强化后,TA15钛合金晶体内部形成了大量的高密度位错和位错墙;同时在材料表面引入高达-500 MPa的残余压应力,可以平衡疲劳载荷作用下产生的拉应力,有效抑制疲劳裂纹萌生并减缓裂纹扩展速率。激光冲击强化可以大大提高钛合金双孔结构的疲劳寿命,相对于未强化试样提高了60%~89%,这是由于激光冲击强化引入的较大残余压应力使得裂纹尖端的有效应力强度因子大大减小,当有效应力强度因子小于材料的断裂韧性时,疲劳裂纹的扩展会被抑制或停止,从而提高疲劳寿命。TA15 titanium alloy were treated by laser shock peening(LSP) to study the effect of LSP on microstructure and fatigue property of the titanium alloy specimens with double holes.The results show that when the specimens are treated by LSP with laser energy of 25 J,circular spot diameter of ?4 mm and shock times of 2,a large number of high-density dislocations and dislocation walls are formed in the TA15 titanium alloy crystal,and introducing residual compressive stress of up to-500 MPa simultaneously on the material surface which can balance the tensile stress generated under fatigue load,effectively suppress fatigue crack initiation and slow down crack propagation rate.The LSP can obviously improve the fatigue life of the titanium alloy specimens with double holes,which is increased by 60%-89% compared to that of the untreated specimen.This is because the large residual compressive stress introduced by LSP greatly reduces the effective stress intensity factor at the crack tip.When the effective force intensity factor is less than the fracture toughness of the material,the fatigue crack growth will be suppressed or stopped,thus improving the fatigue life.

关 键 词：激光冲击强化 TA15钛合金双孔结构 显微组织 残余压应力 疲劳性能 

分 类 号：TG178[金属学及工艺—金属表面处理]