Understanding the fatigue behavior at variable amplitude loadings, as well as being able to reliably predict fatigue life, is very important for most uses of titanium and magnesium light alloys.

We were able to characterize selected titanium and magnesium alloy specimens at constant and variable amplitude tests by measuring mechanical stress-strain hysteresis and temperature as well as associated changes in microstructure. We found that the relationship between stress amplitude and cyclic plastic strain, and temperature changes formed the basis for estimating fatigue behavior as well as predicting the fatigue lifetime of the alloys.