Thermal Stability of Microstructure and Mechanical Properties of Ultrafine-Grained Pure Titanium

摘要

Thermal stability of microstructure was investigated of ultrafine-grained (UFG) pure titanium subjected to anneal at 300℃, 400℃, 500℃ and 600℃. Hardness variety was used to evaluate the effect of annealing temperature on mechanical properties in UFG titanium. Microstructural observation showed that the average grain size slightly increased in UFG pure titanium annealed below 400℃, while the dislocation density significantly decreased. As the annealing temperature increased to 500℃and 600℃, the average grain size dramatically increased and dislocation density sharply reduced. The hardness almost remained constant, when the annealing temperature was 300℃, while it gradually decreased, as the annealing temperature increased to 400℃. The hardness dramatically decreased in the samples annealed at 500℃ and 600℃. The relationship between the microstructural stability and mechanical property variety in UFG Ti during annealing is discussed.