旋片喷丸强化对2024铝合金预拉伸板疲劳性能的影响

摘要

采用成组对比法分析了中心开长圆孔的2024铝合金预拉伸板在旋片喷丸强化前后的疲劳性能,通过三维数码显微镜和X射线应力测试仪对其断口形貌和喷丸强化前后孔壁表面的残余应力进行了分析.结果表明:经旋片喷丸强化后,2024铝合金预拉伸板在180 MPa与168 MPa应力下的疲劳中值寿命分别提高了1.727~2.728倍与1.606~2.110倍;经旋片喷丸强化后,2024铝合金表面形成了大约300 MPa的残余压应力,疲劳裂纹源的萌生区域减小且位于铝合金的内部,提高了铝合金的疲劳性能.%The fatigue properties of 2024 aluminum alloy prestretching sheet with an obround hole in the center before and after flap peen hardening were analyzed by group comparison method.The fatigue fracture and the residual stress of the surface of the hole wall before and after flap peen hardening were analyzed by three-dimensional digital microscope and X-ray stress tester.The results show that the median fatigue life of the 2024 aluminum alloy prestretching sheet increased by 1.727-2.728 times and 1.606-2.110 times,respectively,when loading stress were 180 MPa and 168 MPa.Flap peen hardening introduced 300 MPa residual compressive stress on the surface of aluminum alloy 2024,and the initiation region of the fatigue crack source reduced and located inside the aluminum alloy,and thus the fatigue properties of the aluminum alloy were improved.