Fatigue Properties and Fracture Mechanism of Aluminum Alloy with Orifice Chamfer and Pre-corrosion Damage
Song ZHOU1,2, Lei WANG1, Chuang MA1, Lin-qing YANG1, Liang XU1, Li HUI1,*()
1 Key Laboratory of Fundamental Science for National Defense of Aeronautical Digital Manufacturing Process, Shenyang Aerospace University, Shenyang 110136, China 2 Department of Mechanical Engineering and Automation, Northeastern University, Shenyang 110004, China
Fatigue fracture often occurs because of the corrosion damage to aerospace structural aluminum alloy with holes. Fatigue tests of 7075 aluminum alloy of both unchamfered and chamfered double-hole specimens under uncorrosion and 24h pre-corrosion were carried out. The influence of both pre-corrosion damage and orifice chamferer on fatigue properties and the differences of fatigue fracture characteristics were analyzed. The results show that the effect on fatigue life of pre-corrosion damage is significant. Median fatigue lives of both unchamfered and chamfered double-hole specimens under 24h pre-corrosion decrease about 31.74% and 26.92% compared with uncorrosion specimens. The orifice chamferer have a certain effect on fatigue life of both uncorrosion and 24h pre-corrosion specimens, with median fatigue lives decreased about 28.02% and 15.36% compared with unchamfered specimens, the main reason is due to the stress concentration after orifice chamfered, on the other hand, cutting marks lead to pre-damage during the orifice chamfering process which will result in an increase of the fatigue crack initiation sites and the fracture probability.
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