Analysis of dynamic recrystallization mechanism in γ-TiAl intermetallic compound based on texture measurement

Abstract

The mechanism of dynamic recrystallization of Ti-52mol%Al was discussed on the basis of texture measurements. Uniaxial compression tests were conducted using temperatures and strain rates ranging from 1273 to 1473 K and from 4·0 × 10−5 s−1 to 8·0 × 103 s1, respectively. Formation of a fiber texture with the main component approximately given as {032) (compression plane) was found in all the deformation conditions. The deformation conditions do not affect the profile of pole density distribution but have a strong effect on the texture sharpness. The texture sharpens with increasing temperature and decreasing strain rate. It is concluded that development of the texture originates from the forma- tion of new grains by the bulging process. When the bulging process does not dominate the formation of new grains, the texture sharpness varies depending on the strain necessary for the recrystallization which occurs repeatedly during thedeformation. The strain rate sensitivity exponent (the m value) is 0·2 even when the size of new grains is below 10 μm, suggesting that the predominant mechanism of deformation is crystal slip. This is in good agreement with the texture sharpening with an increase in strain rate at 1273 K.