The Phase Transformation and Microstructure Evolution during Heating of Ti2 Al-Nb-based Alloys

摘要

In this paper, the phase transformation and microstructure evolution during heating of Ti2AlNbbased alloy have been investigated by a dilatome-try, X-ray diffraction and scanning electron microscopy. Results show that phase transformation in Ti2AlNbbased alloy during heating included four stages,B2+α2 →O,O→B2,O→α2 and α2→B2. Accordingly,the expansion rate is approximate to linear,and then the dilatation law was a slight increase and at last becomes a constant. With proceeding of heating from lower temperature,O lamellar immerges in B2 matrix,and then transforms to α2,and finally α2 particles diminish in B2 matrix.