Effect of aging on microstructure and mechanical properties of TC18 titanium alloy
Taking TC18 titanium alloy as the research object,the solid solution-ageing process was used to adjust its organisational structure,and the effects of aging heat treatment and grain organisation on the mechanical properties of TC18 alloy were investigated by combining organisational analysis methods such as X-ray diffraction(XRD),metallography(OM),scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The results show that the alloy's strength in the as-cast state is enhanced after aging compared to that of the solid solution state,but the plasticity is reduced.Under air-cooled solution conditions,the yield strength of the samples increases to 1 492 MPa at the temperature of 450℃and an aging time of 4 h,but their elongation decreases.When the time-effecting temperature is 600℃,there appears fine grain-like secondary α-phase in the samples near the grain boundary and the intragranular,and the distribution and width of the secondary α-phase affect the movement of dislocations in the deformation of the alloy,which reduces the alloy strength and improves the plasticity of the alloy.