A method for carburizing and modifying the surface of high-entropy alloys

Abstract

The invention discloses a high-entropy alloy surface carburizing modification method. The method comprises the steps that (1), an HfZrTiTa high-entropy alloy is pre-treated; (2), active carbon is selected as a carburizing agent, a carburizing container is naturally filled with the carburizing agent, and the pre-treated HfZrTiTa high-entropy alloy is buried into the upper middle portion of the carburizing agent; (3), the carburizing container is sealed; and (4), the sealed carburizing container is placed into a heating device, heating is conducted till the temperature is 700-900 DEG C, then heat preservation is conducted for 2-10 h, after treatment is finished, the carburizing container is taken out for air cooling, then a sample subjected to carburizing treatment is taken out to be subjected to ultrasonic washing and drying, and a high-entropy alloy with the surface subjected to carburizing modification is obtained. According to the high-entropy alloy surface carburizing modification method, the surface hardness and the high-temperature oxidation resistance of the HfZrTiTa high-entropy alloy can be effectively improved at the same time.

Description

Technical field [0001] The invention belongs to the field of coating preparation, relates to the field of multi-principal element high-entropy alloy materials, and particularly relates to a method for surface carburizing modification of high-entropy alloys. Background technique [0002] High-entropy alloy refers to a new type of alloy that contains 5 to 13 alloy elements, each with a content of 5% to 35%, which can form a high-entropy solid solution. There is no alloying element with a content of more than 50% in the high-entropy alloy, and there is no difference between the main element and the minor element in the entire alloy system. Research has found that the high-entropy alloy system embodies a multivariate collective effect, with high strength, high hardness, high wear resistance and other characteristics. Due to the special combination of various metal elements, high-entropy alloys present four major effects: (1) High-entropy effect, the alloy will form a simple solid so...

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Problems solved by technology

(2) Lattice distortion effect, due to the difference in atomic radius between elements, causes lattice distortion, affects the physical and chemical properties of the alloy; leads to solid solution strengthening, affects the electrical conductivity, magnetism, thermal conductivity, etc. of the alloy

(3) Diffusion hysteresis effect, the synergistic diffusion between various elements is very difficult, and severe lattice distortion will slow down the diffusion rate of elements, so the phase separation is very slow at high temperature, and even inhibited and delayed to low temperature

This research also involves the high-temperature oxidation resistance of the material, but the oxidation assessment condition is 800°C for 40 hours, which is far from the expectation of using high-entropy alloy materials for superalloy materials.

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