Effect of cryogenic treatment on the fatigue crack propagation behavior of 7075 aluminum alloy

Abstract. This paper studied the effect of cryogenic treatment on the fatigue crack propagation property of 7075 aluminum alloy at a series of cryogenic temperatures using mechanics testing. Three cryogenic temperatures were chosen for cryogenic treatment:-60℃,-120 and ℃-196. ℃ The result showed that cryogenic treatment, especially at the cryogenic temperature of-120, can significantly ℃ improve the fatigue performance. The X-ray diffraction (XRD) result showed the cryogenic treatment caused the XRD diffraction peak intensity of (200) obvious enhanced. The tendency of XRD diffraction peak intensity of (200) was in good consistence with that of fatigue crack propagation behavior of 7075 aluminum alloy after cryogenic treatment. Therefore, the mechanism for the improvement in fatigue crack propagation property is proposed to be the preferred orientation of crystalline grains through cryogenic treatment.