Hot isostatic pressure near-net forming method for semi-solid complex difficult-machining compact piece

Abstract

The invention discloses a hot isostatic pressure near-net forming method for a semi-solid complex difficult-machining compact piece. The hot isostatic pressure near-net forming method comprises the steps that a semi-solid material is used as a forming material, graphite is used as an internal form control core, the hot isostatic pressure temperature is selected as the solid-liquid two-phase interval temperature, and the compact piece in a complex shape is directly formed under coupling of temperature and pressure. According to the hot isostatic pressure near-net forming method for the semi-solid complex difficult-machining compact piece, performance defects caused by powder surface pollutants in traditional methods can be effectively overcome, and the part forming precision can be effectively ensured through high pressure at the high temperature; in addition, the temperature close to the melting point of an alloy material is adopted, and a solid-liquid coexisting phase occurs in a ladle sleeve at the temperature; due to the fact that liquid phase components exist among crystal grains or solid phase particles, the solid phase particles almost have no binding force and are very low in flow deformation resistance, and a complex runner in the form control core is filled with parent metal advantageously; and moreover, the solid phase particles are easy to separate on specification portions, and while, due to the fact that the liquid phase components exist, the separated portions are very easy to connect integrally.

Description

technical field [0001] The invention belongs to the field of advanced manufacturing, and in particular relates to a method for near-net hot isostatic pressing of semi-solid complex and difficult-to-machine dense parts, which is used for parts with difficult-to-machine and complex shapes of hot isostatic pressing forming materials, and the method is especially suitable for manufacturing aerospace Parts with complex structures. technical background [0002] Nickel-based and titanium-based alloys are widely used in aerospace because of their good comprehensive properties. Nickel-based alloys have the characteristics of good thermal fatigue resistance, low thermal expansion coefficient, and high elastic modulus, and are widely used in hot-end parts such as aerospace engines and industrial gas turbine turbines; titanium alloys have high specific strength, high thermal strength and durability Strength, low crack growth sensitivity under vibration load and impact load, and good co...

AI Technical Summary

Problems solved by technology

[0004] However, the hot isostatic pressing powder near-net shape technology also has certain defects.

In the forming process of parts with complex structures and long straight structures, it is difficult for the powder to achieve densification under the driving force of the sheath deformation, and it is easy to generate pores, so that the performance of the parts cannot meet the requirements

If the pressure is increased to increase the driving force, the sheath may deform too much and crack

Therefore, in hot isostatic pressing parts, there are porosity defects in complex structural parts and long straight parts

In addition, due to the existence of a certain amount of oxide and organic impurities on the powder surface, when the powder particle boundaries are metallurgically bonded to each other, defects such as coarse structure, composition segregation, and insecure bonding will appear, and the particle boundaries where the powder contacts each other are often the source of cracks. Germination point

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