High-strength, corrosion-resistant and medium-entropy alloy and preparation method thereof

Abstract

The invention discloses a high-strength, corrosion-resistant and medium-entropy alloy and a preparation method thereof. The component of the medium-entropy alloy is (CoCrNi)(100-x)Mnx, the atomic ratio of Co to Cr to Ni is (0.5-1):(0.5-1):(0.5-1), the value range of x is 1at%-10at%, , the alloy is formed through mixing, smelting, homogenizing treatment, rolling and heat treatment machining, the grain size of the alloy ranges from 30 mu m to 200 mu m, the manganese-rich phase is separated out of the grain boundary, the tensile strength of the alloy is higher than 1,200 MPa, the ductility is higher than 10%, the corrosion potential ranges from negative 0.43 V to negative 0.26 V, and the medium-entropy alloy is applicable to marine engineering equipment. The preparation process route of the alloy includes vacuum smelting, suction casting, homogenizing annealing, cold rolling and heat treatment. Co, Cr and Ni with the purity being 99% or higher are selected and weighed according to the proportion and are smelted repeatedly in a vacuum smelting furnace, suction casting forming is performed after the component is uniform, multi-pass cold rolling is adopted after annealing treatment, a plate which is 1-2 mm thick is obtained, the tensile strength of the plate is higher than 1,200 MPa, the ductility is higher than 10%, and the corrosion potential ranges from negative 0.43 V to negative0.26 V.

Description

technical field [0001] The invention belongs to the technical field of material processing, and in particular relates to a high-strength corrosion-resistant medium-entropy alloy and a preparation method thereof. Background technique [0002] From the perspective of alloy mixing entropy, alloys can be divided into high-entropy alloys (ΔSmix>1.6R), medium-entropy alloys (1.6R≥ΔSmix≥1R), and low-entropy alloys (ΔSmix<1R). The existing alloys are basically Low-entropy alloys, such as steel, aluminum alloy, titanium alloy, etc. High-entropy alloys, also known as multi-principal alloys, have received widespread attention due to their excellent performance. At present, a series of high-entropy alloys have been developed, such as FeCoNiCrMn high-entropy alloys, which increase in strength as the temperature decreases, and NbWTaMo high-entropy alloys. Has very good high temperature resistance. However, due to the high cost and unstable performance of many high-entropy alloys, ...

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Problems solved by technology

However, the preparation of the above method is cumbersome, the mechanical alloying time is long, and more impurities are easily brought in during the process, and the energy consumption is high, and the output rate is low, which is not conducive to industrial production.

[0004] At present, there have been many studies on the excellent low temperature properties of CoCrNi medium entropy alloys, but there are few studies on their room temperature properties and corrosion resistance.

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