固溶处理对热压CoCrW合金组织及力学性能的影响

EFFECT OF SOLID SOLUTION TREATMENT ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF HOT-PRESS CoCrW ALLOYS

利用SEM,XRD和TEM等分析手段研究了固溶处理对热压烧结CoCrW合金相组成的影响,通过硬度测试、室温拉伸和摩擦磨损实验,研究了固溶处理对热压烧结CoCr W合金力学性能的影响.结果表明,热压态与固溶态CoCrW合金的组成相均为M_(23)C_6,M_6C,CrCo金属间化合物和γ-Co基体;固溶处理降低了合金中的M_(23)C_6含量和原始颗粒边界数量,同时改善了合金塑性和耐磨性能.合金室温硬度和抗拉强度均随固溶温度升高、固溶时间延长而先增高后降低.

Co-based alloy has high strength, good corrosion and wear resistance, and is widely used in aviation industry, nuclear industry. The cast Co-based alloys has high hardness brittleness, but the toughness is low, which limits its wide use. The CoCrW alloy prepared by powder metallurgy process has high toughness, at the same time, the mechanical properties of the CoCrW alloy can be changed by heat treatment. In this work, the effect of solid solution treatment on the microstructure and mechanical properties of the hot pressed alloy was studied by SEM, XRD and TEM, hardness test, room-temperature tensile and wear experiment. The results show that the mi- crostructure of the as-hot pressed and solid solution state CoCrW alloy are both composed of M23C6, M6C, CrCo intermetallic compounds and γ-Co matrix, the contents of M23C6 and prior particle boundaries decrease remarkably after solution treatment, meanwhile, the toughness and wear resistance of the alloy are improved. With the increase of solid solution temperature and time, the hardness and tensile strength at room temperature of CoCrW alloys increase first and then decrease.