Titanium alloys are based on titanium , with their properties regulated by the addition of alloying elements. The chemical composition system directly determines the phase composition and macroscopic characteristics of the material. Titanium is the fundamental element of titanium alloys, typically accounting for more than 50%, and in some high-purity titanium alloys, it can exceed 90%.
Aluminum is one of the most commonly used alloying elements in titanium alloys, primarily used to stabilize the α phase in titanium alloys. Under high-temperature conditions, Al can slow down grain growth in titanium alloys, improve the purity of grain boundary regions, and thereby enhance the overall mechanical properties of the material. During the processing of titanium alloys, Al can increase the material's forgeability, which is beneficial for shaping and subsequent treatment of the material.
Vanadium is a key β phase stabilizing element in titanium alloys. V can enhance the tensile strength and hardness of titanium alloys, improving their performance during cutting and hot working processes. At the same time, V has the ability to refine grains, optimize the microstructure of the alloy, improve the heat resistance and corrosion resistance of titanium alloys, and enhance overall performance.
Molybdenum is also a β-phase constituent element in titanium alloys, which can significantly improve the tensile strength, yield limit, and hardness of titanium alloys, to a certain extent enhance their toughness, increase their corrosion resistance in harsh environments (such as high temperature, strong acids, and strong alkalis), and improve their wear resistance. At the same time, an appropriate amount of Mo can enhance the machinability and weldability of titanium alloys.
In addition to the aforementioned major metallic elements, titanium alloys also contain some impurity elements, such as oxygen (O), nitrogen (N), carbon (C), and hydrogen (H). The content of these elements in titanium alloys must be strictly controlled, as excessive amounts can lead to a decrease in the performance of the alloy. For example, O and N have high solubility in the α phase, which can cause lattice distortion and enhance the strength of the alloy, but at the same time, they can also reduce the toughness of the alloy.
