Effect of ultrasonic peening treatment on the fatigue behaviors of a magnesium alloy up to very high cycle regime

• DOI: 10.1016/j.jma.2021.07.028
• Publication Date: 2021-09-05T10:59:24Z
• Authors: Yao Chen; Fulin Liu; Chao He; Lang Li; Chong Wang; Yongjie Liu; Qingyuan Wang
• Keywords: Mining engineering. Metallurgy; Crack initiation mechanism; Nanograins; 0203 mechanical engineering; Ultrasonic peening treatment; Fine granular area; TN1-997; Very-high-cycle fatigue; 02 engineering and technology

Ultrasonic fatigue tests are performed on a magnesium alloy with and without ultrasonic peening treatment (UPT). Surface enhancement layer leads to the complete change of crack initiation sites. However, mechanism keeps same results in single-faceted morphology at site. Microcracks initiate as Mode II within original grain, but deflect I outside cracked grain. A threshold SIF value is proposed evaluate retarding effect grain boundary microcrack propagation. Outside propagation below ΔKσ-th responsible for formation fine granular area (FGA, nano-grain layer). Based Numerous Cyclic Pressing (NCP) model, it that type should be another necessary condition FGA.