激光冲击强化对7050铝合金小孔结构残余应力和疲劳性能的影响

doi:10.13251/j.issn.0254-6051.2021.11.036

摘要/Abstract

摘要： 研究了激光冲击强化对7050 T7451铝合金小孔结构显微硬度、残余应力和疲劳性能的影响。结果表明:当激光能量为30 J、光斑直径ø4 mm,冲击2次时,7050 T7451铝合金显微硬度显著提高,表层硬度相对于母材提高约12%且硬化层深度可达1 mm;残余压应力幅值超过300 MPa,影响深度可达约1 mm,明显大于喷丸强化残余应力影响层深度。激光冲击诱导的残余压应力可提高疲劳裂纹的萌生抗力,其较深的残余压应力层则有利于延长裂纹的扩展寿命。激光冲击强化后小孔结构疲劳寿命相对于母材提高了4.7~17.6倍,且其疲劳寿命增益及稳定性明显优于喷丸强化。

关键词: 激光冲击强化, 7050 T7451铝合金, 孔结构, 显微硬度, 残余压应力, 疲劳性能

Abstract: Effect of laser shock peening on microhardness, residual stress and fatigue property of the 7050 T7451 aluminium alloy with hole was studied. The results show that when the laser energy is 30 J, circular spot diameter is 4 mm and the shock times are twice, the microhardness of the 7050 aluminium alloy increases obviously, the surface microhardness increases by 12% compared with the base material, with the hardened layer of 1 mm. The amplitude of residual compressive stress exceeds 300 MPa, and the influence depth of residual compressive stress can reach about 1 mm, which is significantly greater than the depth of influence layer strengthened by shot peening. The residual compressive stress can improve the initiation resistance of fatigue crack, and the deeper influence layer of residual compressive stress is beneficial to prolong the crack growth life. Laser shock peening can obviously improve the fatigue life of the aluminum alloy with hole, which is increased by 4.7 times to 17.6 times compared to that of the untreated specimen, and the fatigue life gain and stability are obviously better than those of shot peening.

Key words: laser shock peening, 7050 T7451 aluminium alloy, hole structure, microhardness, residual compressive stress, fatigue property

中图分类号:

TG156

韩培培, 焦清洋, 权纯逸, 赵栋, 孙汝剑, 车志刚. 激光冲击强化对7050铝合金小孔结构残余应力和疲劳性能的影响[J]. 金属热处理, 2021, 46(11): 202-206.

Han Peipei, Jiao Qingyang, Quan Chunyi, Zhao Dong, Sun Rujian, Che Zhigang. Effect of laser shock peening on residual stress and fatigue property of 7050 aluminium alloy with hole[J]. Heat Treatment of Metals, 2021, 46(11): 202-206.

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