ANALYSIS OF THE MECHANISM OF DYNAMIC RECRYSTALLIZATION IN GAMMA-TIAL INTERMETALLIC COMPOUND BASED ON TEXTURE

Uniaxial compression tests were conducted on the Ti-52 mol%Al intermet allic compound at the temperatures and strain rates ranging from 1173 to 1473 K and 4.0 x 10(-5) to 5.0 x 10(-3) s(-1), respectively. The me chanism of dynamic recrystallization of the compound was examined on t he basis of texture analysis. A fiber texture was formed during dynami c recrystallization. The main component of the texture is given approx imately by (032) (compression plane) irrespective of the deformation t emperatures, strain rates and strains. The sharpness of the texture va ries depending on strains and the peak stresses appearing in the true stress-true strain curves. Thus the texture formation should be attrib uted to the deformation process; the recrystallization process has an effect of changing the texture sharpness. One to one correspondence ex ists between the texture sharpness and the peak stresses when the text ure sharpness is evaluated at true strains about -1.7. When the peak s tress is low, the texture sharpens monotonously with increasing strain , whereas the textures at high peak stresses stop developing at the st rains more than -1.0. These results suggest that the dynamic recrystal lization proceeds by the mechanism succeeding to the formation of the texture by crystal slip at low peak stress conditions and the mechanis m at high peak stress disturbs the texture development. The existence of the two different mechanisms which have been proposed by microstruc tural observation, namely strain induced grain boundary migration and the nucleation and growth mechanism, are elucidated by the texture ana lysis.