Near-net-shape forming method of refractory metal part

Abstract

The invention discloses a near-net-shape forming method of a refractory metal part, aiming at solving the complexity and the time consumption of a PM (power metallurgy) molding mode, and compensating the technical defect that the comprehensive property of an alloy cannot brought into play completely due to the fact that an SLM (selective laser melting) method liquid phase quantity cannot achieve the technical index of 30-35Vol / % of the densification. The method provided by the invention is as follows: 1, three-dimensional modeling software is adopted to design a CAD (computer-aided design) of a part, subsequently multiple layer slicing information is generated by slicing processing software, and an STL (Standard Template Library) file is stored, and the data of the STL file is transmitted to an SLM rapid molding system; 2, a layer of metal powder to be machined (the thickness ranges from 0.02-0.2mm, and the particle diameter is about 10-100 micrometer) is paved on a working platform by a powder conveying mechanism; 3, an optical fiber laser is adopted to scan the slicing, and the metal powder to be machined paved in the step 2 is completely melted, wherein the scanning speed is 50-1000mm / s; and 4, the steps (2) and (3) are repeated till the whole part machining is ended. The method has the beneficial effects that the powder is subjected to alloying, the bonding property of the alloy is improved, thereby being beneficial for the filling and the molding densification of the liquid, and improving the comprehensive property of the alloy.

Description

technical field [0001] The invention belongs to the field of rapid prototyping technology and powder sintering composite forming, in particular to a method for near-net-shaped refractory metal parts. Background technique [0002] Refractory material is a pure metal or alloy material composed of tungsten, molybdenum and other refractory metals or some other elements. Compared with traditional alloy materials, the typical characteristics of refractory materials are high melting point, usually around 3000°C, so it is difficult to cast and smelt, and powder metallurgy is often used for processing. In recent years, refractory material parts have been widely used due to their excellent properties; taking tungsten-based alloys as an example, they have the following excellent properties, such as high density, good tensile strength, good ductility, and good radiation absorption ability, good electrical conductivity, thermal conductivity and low thermal expansion coefficient, good co...

AI Technical Summary

Problems solved by technology

[0005] (1) Powder metallurgy liquid phase sintering method is difficult to directly form parts with arbitrary complex shapes

In the application of refractory materials, if a certain complex shape is required, the powder metallurgy liquid phase sintering method cannot be directly formed due to the limitation of the process

In actual production, mechanical processing and follow-up processing are often required. This method is not only cumbersome, low production efficiency, but also causes waste of materials.

[0006] (2) The powder metallurgy liquid phase sintering method needs to use a mold for forming, and the parts need to be removed from the mold after the processing is completed. Therefore, the design of the mold and the control of the sintering process are very important. The process control is difficult, and a slight deviation will cause Affects the dimensional accuracy of the part

However, PIM still does not deviate from the liquid phase sintering densification principle of traditional PM, and there are the following shortcomings: (1) Before degreasing and sintering, the density of the blank of the part is low; (2) Bubbling, bending, and cracking are easy to occur during the degreasing process of the blank , collapse and other defects, currently only suitable for the preparation of small parts; (3) The whole process requires mold support, so it is impossible to manufacture parts with extremely complex structures, such as curved surface impellers, three-dimensional mesh structure parts, etc., and the required molds are expensive