2024 Volume 74 Issue 2 Pages 99-104
Rotating bending fatigue tests were conducted for Mg-Al-Ca alloy thick plates with different compositions (extruded Mg-4%Al-1%Ca (AX41, 20 mm thickness) and extruded Mg-9%Al-1%Zn-2%Ca (AZX912, 14 mm thickness), and microstructural observation was made to clarify the effects of microstructural factors on the fatigue properties of the alloys. Strong basal texture, in which basal plane was inclined to the transverse direction, was formed in both AX41 and AZX912. Hence, the yield stress of AX41 and AZX912 exhibited large anisotropy. The results of rotary bending fatigue test showed larger anisotropy of fatigue strength in AX41 as well as the tensile tests. It was suggestedthat the strong texture formation has a large effect on fatigue strength similar to the tensile tests. The fatigue strength of AZX912 thick plate obtained by rotary bending fatigue test was comparable to that of AZX912 medium plate (3 mm thickness) obtained by plane bending fatigue test. The reason was that the coarse second-phase particles more than 30 μm were found in the AZX912 medium plate as well as in the AZX912 thick plate, although in small amounts.
