以铸造CoCrW合金为研究对象, 通过XRD, SEM和EDS分析以及硬度测试和室温耐磨实验, 研究了不同温度的固溶处理对该合金的组织及耐磨性能的影响. 结果表明, 铸态和固溶态CoCrW合金组织均由M23C6, M6C和γ-Co基体3种相组成, 但固溶后合金中碳化物的大小、形貌及分布发生明显变化. 固溶后合金中起强化作用的碳化物大量溶解, 使合金硬度和耐磨性能降低; 随着固溶温度的升高, 部分碳化物中的Cr, W等合金元素大量固溶到基体中, 提高了基体的强度, 使合金的硬度和耐磨性能有所提高; 铸态和固溶态CoCrW合金的磨损机制均为磨粒磨损、黏着磨损和氧化磨损的共同作用.
CoCrW alloy is a kind of stellite alloy, which has high strength, good wear resistance, and is widely used in aviation industry, nuclear industry and other fields. For a long time, the CoCrW alloy is mainly used as coating to have an effect on wear and the corrosion resistance. With the development of the industry, the conventional cast CoCrW alloy has been widely studied. The mechanical properties of the cast CoCrW alloy can be changed by heat treatment, which is of high hardness and great brittleness. In this work, hardness and wear-resistant properties of the CoCrW alloys as-cast and after solution treatment were studied by combining XRD, SEM, EDS, hardness test and wear resistance test, and effects of the solution temperature on the microstructure and wear-resistant properties were also investigated. The results showed that the microstructures of the CoCrW alloys as-cast and after solution treatment were both composed of M23C6, M6C and γ-Co matrix, but the size, morphology and distribution of carbides occurred in the alloy changed obviously by solution treatment. The dissolution of a large amount of carbides in the alloy after solution treatment was mainly responsible for the decrease in hardness and wear resistance of the alloy compared with that of the as-cast one. With the increase of the solution temperature, the Cr, W and other alloying elements in the carbides were dissolved into the γ-Co matrix so as to strengthen the matrix resulting in the improvement of the hardness and the associated wear resistance of the alloy. The mechanism that controlling the wear-resistant property of CoCrW alloys as-cast and after solution treatment was the interaction of abrasive wear, adhesive wear and oxidation wear.
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