Analysis of the performance characteristics and smelting process of TA1 titanium alloy
As a representative material of industrial pure titanium, TA1 titanium alloy has excellent overall properties, including good corrosion resistance, high specific strength and good durability. Based on the characteristics and influencing factors of the durability of TA1 titanium alloy, the influence of the melting process on its performance is discussed in detail.
1.Characteristics of endurance properties of TA1 titanium alloy
The endurance properties of TA1 titanium alloy are an important aspect of its material properties, including tensile strength, yield strength and fatigue strength. In general, at room temperature, TA1 titanium alloy tensile strength is 240-340 MPa, yield strength is about 180-275 MPa, elongation is 20-35%. In high temperature environments, the endurance strength of materials decreases significantly, especially when the temperature exceeds 400°C.
The rupture strength of TA1 titanium alloy decreases gradually under long-term load. According to the experimental data, the rupture strength of TA1 titanium alloy after 1000 hours is about 200 MPa at 200 ℃, but only 120 MPa at 400 ℃, showing that the rupture strength decreases obviously with the increase of temperature.
Creep performance at high temperatures: The creep behavior of TA1 titanium alloy also has a significant impact on its long-lasting properties. At 500°C, the creep rate reaches more than 0.02%/hour, which is much higher than the creep rate at room temperature. This high-temperature creep characteristic limits the application of TA1 titanium alloy in high-temperature structural parts.
2. Effect of smelting process on the properties of TA1 titanium alloy
The performance of TA1 titanium alloy is largely affected by its smelting process. Different smelting processes directly affect the chemical composition, organizational structure and mechanical properties of the alloy.
Vacuum consumable arc melting (VAR) process
Plasma melting (PAM) process
Electron Beam Melting (EBM) Process
3. Effect of impurity elements on endurance properties
Impurity elements have significant effects on the endurance properties of TA1 titanium alloy, especially oxygen, nitrogen and hydrogen.
Effect of oxygen content: oxygen exists as interstitial solution element in TA1 titanium alloy, and its content increases significantly the strength of the alloy, but at the same time reduces its ductility. The experimental data show that when the oxygen content increases from 0.1% to 0.3%, the tensile strength of TA1 titanium alloy increases from 300 MPa to 350 MPa, but the elongation decreases from 30% to 15%.
4. Requirements of smelting environment for impurity control
The control of the smelting environment is essential to reduce the content of impurity elements.
Vacuum requirements: In VAR and EBM smelting processes, the vacuum is usually required to reach 10^-3 to 10^-4 Pa to effectively reduce the content of gas elements in the alloy. A higher degree of vacuum helps to further reduce the content of hydrogen, oxygen and other elements, thereby improving the long-lasting properties of the alloy.
Choice of protective atmosphere: In the PAM smelting process, high-purity argon gas is usually used as the protective atmosphere. The purity of argon should reach more than 99.999% to prevent the introduction of additional impurity elements during the smelting process.
