DYNAMICS OF RECRYSTALLIZATION BEHAVIOR AND GRAIN GROWTH BEHAVIOR OF Nb-Ti-Al SUPERALLOY

摘要

For industrial and military applications, there is an increasing need for structural materials at elevated temperature beyond nickel-base superalloys. The Nb-Ti solid solution alloy possesses relatively high fracture toughness and good ductility. Some elements such as aluminum are added for better high temperature strength. After annealing, the strengthening phase precipitated in the grain boundary preferentially, and then grew into the grain. In order to control the size of the strengthening phase, the equations of dynamics of recrystallization and grain growth were obtained. After cold deformation, the uniform and tiny grain after annealing at 900-1020°C can be obtained, the relation of volume fraction and annealing time can be described with Avrami equation. The recrystallization activation energy decreases as the increase of cold deformation, at the range of 249.2~208.9 kJ/mol. The influence of temperature and time on the grain growth of the alloy was also studied.