Abstract:The relationships between microstructures and mechanical properties of Ti-55531 titanium alloy were
investigated, by using statistic analysis on the microstructure characteristics, such as width of α platelet, β grain size,
grain boundary α discontinuity and volume fraction of α phase. The results show that,with the increase of the temperature
of annealing, the average β grain size increases from 86 μm to 210 μm, grain boundary α discontinuity decreases,
the volume fraction of needle-like α phase decreases first and then increases. The extension rate, statics toughness
and crack initiation energy decrease while the crack propagation energy increase with the growth of β grain size.
Statics toughness is positive correlated with the grain boundary α discontinuity. There is a positive correlation between
the volume fraction of α phase and yield strength.
