Microstructural evolution during high temperature deformation of lamellar Ti48Al-2Nb-2Cr

The microstructural evolution of lamellar Ti48Al-2Nb-2Cr during deformation at temperatures between 1000 and 1200 K was investigated by light optical and electron microscopy. The lamellar structure which initially covers more than 95% of the volume transforms during deformation into a globular structure consisting of equiaxed subgrains with a significant amount of large angle boundaries (< 30%). The steady state subgrain size and the spacing of dislocations in the subgrain interior vary in inverse proportion to shear modulus normalized stress. Based on the steady state data the evolution of the volume fraction with globular (subgrain) structure and the characteristic spacings is quantified. (C) 1999 Elsevier Science Ltd. All rights reserved.