Fatigue properties of Al-Mg alloy sheets for auto-body application

摘要

The effect of Mg content on fatigue behavior in Al-Mg alloys for auto body applications was investigated in this study.The increase of Mg content in Al-5.5 wt% Mg and Al-6.6 wt% Mgalloys enhanced the tensile strength and elongation from 284 MPaand 26.4% to 321 MPa and 31.2%. But the Al-6.6 wt% Mg alloyshowed lower fatigue strength compared to that of Al-5.5 wt% Mgalloy due to the small precipitates along grain boundaries. Thesesmall precipitates were identified as Al8Mg5 phase which plays animportant role as fatigue crack initiation site. The fatigue limits ofAl-5.5 wt% Mg and Al-6.6 wt% Mg alloys showed 0.56 and 0.44,respectively. The fatigue crack growth rate of M-6.6 wt% Mg alloysheets is faster than that of Al 5.5 wt% Mg alloy sheets.