Mo-Si-B-Hf-Al alloy bar and preparation method thereof

Abstract

The invention provides a Mo-Si-B-Hf-Al alloy bar. The Mo-Si-B-Hf-Al alloy bar is composed of the following ingredients in atomic percent: 6-18% of Si, 7-19% of B, 5-15% of Hf, 6-14% of Al and the balance Mo and inevitable impurities. The invention further provides a method for preparing the alloy bar. The method comprises the following steps: 1. uniformly mixing silicon powder, boron powder, hafnium powder, aluminium powder and molybdenum powder by means of wet ball-milling, carrying out vacuum drying, and then obtaining a mixed powder; 2. sintering to obtain a sintered body; 3. carrying out vacuum self-consuming arc melting to obtain a cast ingot; 4. carrying out hot extrusion to obtain a semi-finished bar billet; and 5. carrying out hot extrusion to obtain the Mo-Si-B-Hf-Al alloy bar. The Mo-Si-B-Hf-Al alloy bar provided by the invention has the characteristics of being low in oxygen content, high in strength, resistant to oxidation, high in room-temperature fracture toughness, and the like, and can be applied to a high-temperature oxidation atmosphere.

Description

technical field [0001] The invention belongs to the technical field of alloy material preparation, and in particular relates to a Mo-Si-B-Hf-Al alloy rod and a preparation method thereof. Background technique [0002] The higher the working temperature of the turbine blade material of the aero-engine, the better the performance of the engine and the higher the efficiency. The thrust-to-weight ratio of the aero-engine has a great relationship with the working temperature of the turbine blade material. At present, nickel-based superalloys cannot meet the requirements of advanced aero-engines, and the next generation of high-temperature structural materials must be developed. Mo-Si-B alloys are formed from in situ self-generated Mo 5 SiB 2 、Mo 3 Composed of Si intermetallic compound phase and molybdenum solid solution (Moss) phase, it has the characteristics of high melting point, high temperature strength and oxidation resistance, and has broad application prospects in the ...

AI Technical Summary

Problems solved by technology

However, a common feature of these Mo-Si-B alloy materials is that they are very brittle at room temperature, and there are defects such as holes and microcracks in the material, which reduce the mechanical properties, oxidation resistance and reliability of the material, resulting in these Mo-Si -B series alloy materials are difficult to be applied in engineering

This is due to the high content of impurity elements and oxygen in Mo-Si-B alloys prepared by traditional powder metallurgy, impurity elements reduce the high-temperature mechanical properties, and brittle oxygen elements are enriched at the grain boundaries, making the material brittle

In addition, the Mo-Si-B series alloy prepared by powder metallurgy is not high in density, and there are a large number of holes or microcracks in the material, which also reduces the room temperature plastic toughness and high temperature mechanical properties of the material. , these holes or microcracks provide channels for the diffusion of oxygen, reducing the oxidation resistance of the material

The microstructure of the Mo-Si-B alloy prepared by the smelting method is composed of coarse columnar cast grains, which reduces the grain boundary bonding strength of the material, and is prone to microcracks due to the anisotropy of the material composition phase. Defects, which deteriorate the comprehensive mechanical properties of the material

Images