Heat treatment of titanium alloy

Commonly used heat treatment methods are annealing, solution treatment and aging treatment. Annealing is to eliminate internal stress, improve plasticity and structural stability, so as to obtain better overall performance. Generally, the annealing temperature of α alloy and (α+β) alloy is selected at 120～200℃ below the (α+β)-→β phase transition point; solid solution and aging place 　　 commonly used heat treatment methods include annealing, solid solution and aging treatment. Annealing is to eliminate internal stress, improve plasticity and structural stability, so as to obtain better overall performance. Generally, the annealing temperature of α alloy and (α+β) alloy is selected at 120～200℃ below the (α＋β)-→β phase transformation point; the solution and aging treatment are rapid cooling from the high temperature zone to obtain the martensite α′ phase and metastable Then the meta-stable phases are decomposed by heat preservation in the middle temperature zone, and the fine and dispersed second-phase particles such as the α phase or compounds are obtained to achieve the purpose of strengthening the alloy. Usually (α+β) alloys are quenched at 40～100℃ below the (α＋β)─→β phase transformation point, and metastable β alloys are quenched at 40～80℃ above the (α＋β)─→β phase transformation point. The aging treatment temperature is generally 450 to 550°C.　　To sum up, the heat treatment process of titanium alloy can be summarized as: 　　 (1) Stress relief annealing: the purpose is to eliminate or reduce the residual stress generated during the processing. Prevent chemical attack and reduce deformation in some corrosive environments.　　 (2) Complete annealing: The purpose is to obtain good toughness, improve processing performance, facilitate reprocessing and increase the stability of size and structure.　　 (3) Solution treatment and aging: The purpose is to improve its strength. α titanium alloy and stable β titanium alloy cannot be strengthened by heat treatment, and only annealing is carried out in production. α+β titanium alloy and metastable β titanium alloy containing a small amount of α phase can further strengthen the alloy through solution treatment and aging.　　 In addition, in order to meet the special requirements of the workpiece, the industry also uses metal heat treatment processes such as double annealing, isothermal annealing, β heat treatment, and deformation heat treatment. Previous: The use of titanium alloys Next: Cutting of titanium alloys