Titanium alloy is favored by people for its excellent mechanical properties at room temperature and high temperature, outstanding corrosion resistance and high strength, and has become an important structural material in aviation, aerospace and other industrial fields. Titanium alloys are divided into titanium alloys, titanium alloys, and + titanium alloys according to their annealed state [I] tissues, and these three materials are used in many parts of the new models.
The heat treatment of titanium alloy can significantly improve the alloy strength and obtain the comprehensive properties of high strength and good plasticity. So when the titanium alloy in heat treatment, what is the performance, and what principles should be observed?
Titanium alloy heat treatment is mainly used to adjust the structure
The microstructure of titanium alloy is determined by thermal deformation, and the heat treatment mainly plays the role of adjustment. For example, heat treatment can only adjust the ratio of the phase and phase obtained by thermal deformation, and the lamellae resulting from overheating cannot be changed to a two-state structure by heat treatment [II].
The intensified heat treatment of titanium alloys is limited by the alloy phase composition. Most near-type and stable type titanium alloys (except ti-2Cu and very few others) cannot be heat-treated and strengthened. Only + type titanium alloys can be heat-treated and strengthened.
Strictly control heating temperature and time
When the titanium alloy is heated above the transition temperature, the grain [III] grows rapidly. During subsequent cooling, the alpha phase first nucleates at grain boundaries [IV] and grows into grains. After the zone heat treatment, the grain size of the zone is large and can be generally visible to the naked eye. Moreover, the coarse grain [V] structure of titanium alloy cannot be eliminated by heat treatment, so it must be changed by forging deformation. Therefore, heating temperature and time should be strictly controlled before forging or heat treatment in zone to prevent grain from growing too much.
