The method of solid solution strengthening preparation of tantalum base alloy with gradient structure is as follows: 1. The tantalum powder is placed in nitriding furnace, and the tantalum powder is treated with oxynitriding; Second, the tantalum powder after oxynitriding treatment is placed in the plasma sintering furnace, and the tantalum powder after oxynitriding treatment is sintered to obtain tantalum base alloy; Third, the tantalum base alloy is placed in a vacuum annealing furnace, and the tantalum base alloy is subjected to vacuum annealing treatment. The method of the invention firstly makes the oxygen nitrogen in the tantalum powder distribute in gradient from the surface to the core through oxynitrizing treatment, and then forms the tantalum base alloy through sintering treatment, and the hardness of the tantalum base alloy also presents gradient distribution from the surface to the core. Finally, the oxygen nitrogen in the tantalum base alloy is gradually diffused from the boundary to the core through vacuum annealing treatment. It can control the mechanical properties of the material in a large range, achieve a good match between the strength and plasticity of the tantalum base alloy, and extend the service life of the material.
At present, the main strengthening methods of tantalum alloy are solid solution strengthening and precipitation strengthening. For example, Ta-2.5W, Ta-7.5W, Ta-12W, Ta-15W series alloys used for many years in aerospace and missile technology rely on solid solution strengthening of tungsten, and its strength increases with the increase of tungsten content, but the processing of tantalum tungsten series alloys is more difficult. In addition, elements such as hafnium and carbon are added on the basis of tantalum tungsten alloy, and the strength performance can be further improved through the solid solution strengthening of tungsten and hafnium and the precipitation phase strengthening of hafnium carbide, but it only reaches about 800MPa. The composition of multi-element tantalum alloy is relatively complex, and the price of added elements such as tungsten and hafnium is relatively expensive, and the processing performance of the alloy is poor. Therefore, the development and research of low-cost high-strength tantalum alloys can not only effectively save the amount of materials, but also expand the application range of tantalum alloys.
The preparation method is simple, the product is compact, the quality is stable, the performance is excellent, and the repeatability is good. The method of the invention not only can obtain low cost near net forming high strength tantalum base alloy parts, but also provides a new idea for strengthening metals, especially refractory metals tantalum and niobium. At the same time, the method can also use cheap carbon or other elements to strengthen the surface of powder particles, which provides a reference for other metals to strengthen treatment, and promotes the progress of metal material strengthening technology.
