Fatigue Properties of Rapidly Solidified Mg-6Zn-1Y-0.6Ce-0.6Zr Alloy Processed by Reciprocating Extrusion

Abstract

The ribbons of rapidly solidified Mg-6wt%Zn-1wt%Y-0.6wt%Ce-0.6wt%Zr alloy were reciprocatingly extruded and forward extruded into dense bar material. Room-temperature fatigue behavior of the alloy was tested in axial tension-tension stress condition. The fracture morphologies of the alloy after fatigue were observed by SEM. The results show that the fatigue limit is 159.2MPa with 106 cycles when the load frequency was 10Hz. The S-N curve of the alloy can be regarded as Type Ⅱ fatigue curve. The fatigue cracks originate from surface or subsurface of the fatigue specimens generally. The second phases or inclusions in these areas were prone to be the crack sources. The high fatigue properties of the alloy can be attributed to grain refinement strengthening and dispersion strengthening resulted from rapid solidification and reciprocating extrusion.