The Fatigue Crack Propagation of Al–Mg–Mn–Zr Alloy with Erbium

Abstract

This study investigated the fatigue crack propagation of Al–Mg–Mn–Zr alloys with erbium. The research found that in this alloy the crack propagation path prefers to extend along the grain boundary. If there are too many second phases or impurities in the gain boundary, the crack propagation will be influenced. The dispersed Al3(Er, Zr) precipitate in the alloy can act as a core of heterogeneous nucleation to attract Mg, Zn and Al element, and reduce the large brittle Al3Mg2second phase appear on the grain boundary, so the fatigue crack propagation rate can be slow down. In addition, these Al3(Er, Zr) precipitate can pin the dislocation in the alloy to reduce stress concentration at the grain boundary, so it also has some positive effect to the fatigue crack propagation.