The method of high performance powder metallurgy titanium aluminum intermetallic compound belongs to the field of powder metallurgy titanium. The invention provides that TiCl2 is evenly mixed with a certain proportion of aluminum powder, and after heat treatment-ball milling - forming-sintering, high-performance titanium and aluminum intermetallic compounds are finally obtained. In the process of powder heat treatment, TiCl2 and aluminum powder undergo REDOX reaction, AlCl3 will remove the matrix in gaseous form, the resulting Ti and Al will further react and diffuse, and the micro-titanium and aluminum intermetallic compound powder will be crushed by ball milling, and the oxygen content will be <0.1wt. % after forming and sintering. High performance titanium aluminum intermetallic compounds with density ≥ 99%. The invention has simple preparation process, can realize the densification of titanium and aluminum intermetallic compound without pressure sintering, and has small grain size. It provides a new idea for the preparation of low oxygen, low cost and high performance titanium aluminum intermetallic compounds, and is conducive to promoting the industrialization development of powder metallurgy titanium aluminum intermetallic compounds.
Titanium aluminum intermetallic compounds have an orderly structure, can still maintain strength and stiffness at high temperature, and has low density, high specific strength, high elastic modulus and good oxidation resistance advantages, is expected to replace nickel-based superalloys in aerospace, national defense and other fields of high temperature structural materials. However, as cast titano-aluminum intermetallic compounds have coarse structure, severe segregation, anisotropy, poor ductility and fracture toughness at room temperature, narrow hot processing window, poor deformation ability at high temperature, and traditional preparation and processing difficulties, which seriously hinder the wide application of titano-aluminum intermetallic compounds. Powder metallurgy technology has the advantages of uniform structure, fine grain and near-net forming, which can directly prepare complex titanium-aluminum intermetallic compound components and avoid hot processing links, which is of great significance for the low-cost of titanium-aluminum intermetallic compounds in powder metallurgy.
At present, prealloying powder method and elemental powder mixing method are mainly used to prepare powder metallurgy Ti-Al intermetallic compounds. Among them, the titanium aluminum intermetallic compounds prepared by pre-alloying powder method have fine grain and good ductility at room temperature, but the cost is high and the process is complicated. Although the element powder mixing method overcomes the above shortcomings, the volume expansion occurs in the sintering process, resulting in cracks and other defects. At the same time, titanium powder and aluminum powder should be used as raw materials in the process of elemental powder mixing, but the oxygen content in the powder is high, and the oxygen in the system can not be removed during the sintering process, resulting in high oxygen content of titanium and aluminum intermetallic compound powder, which seriously affects its mechanical properties.
