Characteristics of metadynamic recrystallization of a high Nb containing TiAl alloy

摘要

Stress relaxation tests were applied to measure the kinetics of metadynamic recrystallization (MDRX) of a high Nb containing TiAl alloy subsequent to plane strain compression tests executed in the temperature range of 1050-1150 ℃ and the strain rate range of 0.01-1 s~(-1). The results showed that MDRX behavior of the alloy was almost independent on pre-strain and deformation temperature, but significantly dependent on strain rate. The Avrami exponents under different deformation conditions were identified to be about 0.40-0.52. The low Avrami exponents indicate a low MDRX rate during interpass annealing, and these low values are mainly ascribed to the weak driving force for MDRX. Moreover, high Nb additions and multiple phases can further decrease the MDRX rate.