Heat Treatment of Nickel-Cast Titanium Aluminium Alloy
Titanium aluminium alloy (Ti-Al alloy) is an important high-temperature alloy with a variety of applications. It has excellent properties such as good oxidation resistance, high mechanical strength, good ductility and excellent creep resistance. The most important element in the alloy is nickel. Nickel-cast Ti-Al alloy has been widely used as a structural material in aviation, aerospace, nuclear reactor and other fields.
The purpose of thermal treatment of nickel-cast Ti-Al alloy is to improve its physical and chemical properties, enhance its strength and reduce its brittleness. The heat treatment process includes heating, soaking and cooling.
Heating: The heating temperature of the nickel-cast Ti-Al alloy is often above the solid solution temperature. The soaking temperature is higher than solid solution temperature because it is necessary to promote the dissolution of nickel in the alloy. After heating, the metallographic structure of the alloy is mainly austenite, and its mechanical properties are greatly improved.
Soaking: The purpose of soaking is to promote the dissolution of nickel in the alloy. The soaking temperature and time should be determined according to the chemical composition of the alloy. Generally, the soaking temperature is higher than the solid solution temperature, and the soaking time is short.
Cooling: After soaking, the alloy needs to be cooled rapidly. Rapid cooling can prevent the alloy from undergoing phase transformation. The cooling rate of alloy should be selected according to the expected properties of the alloy. Generally, the cooling rate should be greater than or equal to the critical cooling rate of austenite transformation.
In summary, heat treatment of nickel-cast Ti-Al alloy includes heating, soaking and cooling. The heating temperature, soaking temperature and cooling rate should be determined according to the chemical composition of the alloy and the expected properties of the alloy. Heat treatment of nickel-cast Ti-Al alloy can greatly improve its physical and chemical properties, enhance its strength and reduce its brittleness.
