EFFECTS OF SOLUTION TREATMENT ON MICRO-STRUCTURE AND WEAR-RESISTANT PROPERTIES OF CoCrW ALLOYS

Abstract

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 wearresistant properties of the CoCrW alloys ascast 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 g-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 g-Co matrix so as to strengthen the matrix resulting in the improvement of the hardness and the associated wear resistance of the alloy. The mecha*国家自然科学基金项目51201161和辽宁省自然科学基金项目2013024011资助 收到初稿日期: 2015-09-17,收到修改稿日期: 2015-11-27 作者简介:何 波,女,锡伯族, 1978年生,副教授 DOI: 10.11900/0412.1961.2015.00488