Effects of heat treatment of creep behavior of a near #alpha# titanium alloy

摘要

Ti-8Al-1Mo-1V(Ti811) alloy is a typical near #alpha# and high temperature titanium ally.By means of OM and TEM its creep behavior for different microstructures obtained by different double annealings are studdies,and effects of Ti_3Al phase on creep behavior are analysed.The results suggest that acicular structrue exhibits the best creep behavior,equiaxed one is the second and bi-modal one is the least.The influences of structures on creep behavior are controoled by the mobility of dislocations,The decrease of equiaxed #alpha# phase content is beneficial for the dislocation to slip to the #beta# phase and for the grain boundary gliding,which resuits in decrease of creep resistance.The prescipitates of Ti_3Al phase retard slip,strengthen matrix and increase eastic modulus of the matrix,which causes the creep resistance to increase.