Fatigue behaviour of pre-strain 7B04-T7451 aluminum alloy
(1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Northeast Light Alloy Co Ltd, Harbin 150060, China)
2. Northeast Light Alloy Co Ltd, Harbin 150060, China)
Abstract: The effect of minimum and the maximum stresses on the fatigue behaviour of a 30 mm thick plate of a 7B04-T7451 (Al-Zn-Mg-Cu) subjected to a tensile pre-strain level of 2％ was investigated, including the fatigue crack growth (FCG) rate, microstructure observation, fractographic examination and fatigue S-N curve, etc. The results show that the characteristics of fatigue facture can be observed obviously under high cycle fatigue condition, and the higher the stress amplitude, the wider the space between fatigue striations, the faster the rate of fatigue crack developing and going into the intermittent fracture and the greater the ratio of the intermittent fracture area to the whole fracture area.
Key words: 7B04-T7451 aluminum alloy; high cycle fatigue; fatigue crack growth rate; endurance limit