Fatigue behavior of hot-extruded Mg-10Gd-3Y magnesium alloy

摘要

In this study, the influence of T5 heat treatment on tensile and fatigue behavior of hot-extruded Mg-10Gd-3Y (wt%) magnesium alloy has been investigated. High cycle fatigue tests were carried out at a stress rate (R) of - 1 and a frequency of 100 Hz using hourglass-shaped round specimens with a gauge diameter of 5.8 mm. The results show that fatigue strength (at 10~7 cycles) of Mg-10Gd-3Y magnesium alloy increases from 150 to 165 MPa after T5 heat treatment, i.e., the improvement of 10% in fatigue strength has been achieved. However, the crack growth resistance is lowered by T5 heat treatment. Results of microstructure observation and scanning electron microscopy-energy dispersive x-ray (SEM-EDX) analysis suggest that the fatigue strength in the Mg-10Gd-3Y magnesium alloy is determined by the threshold stress of basal slip, which is induced by solid solution hardening and precipitation hardening.