摘要：本文主要研究热处理工艺对CoCrNiNb0.46完全共晶多主元合金组织及性能的影响。对试样采用700，800，900及1000℃热处理，保温24小时，水冷。另外，对合金分别进行1000℃保温24h采用炉冷、空冷处理；900℃保温时间延长至48、72小时热处理。对热处理后合金进行压缩实验、硬度测试、SEM、XRD等分析测试，以研究不同热处理工艺对CoCrNiNb0.46合金的组织及性能的影响。结果表明，700℃热处理后合金的微观组织具有良好的热稳定；当温度超过900℃时共晶组织开始出现弯曲，1000℃后共晶组织球化严重。合金进行1000℃热处理之后，层片状组织消失，合金中不同区域Nb含量几乎一致。Nb元素在合金的整个组织中几乎呈现平均分布。热处理后的合金相组成并没有发生改变，均由FCC和Laves两相组成。进行热处理后合金中FCC相体积分改变。对热处理后的试样进行压缩实验后发现热处理后合金的抗压强度均低于铸态，800℃热处理后的抗压强度最低为615MPa，1000℃炉冷后合金的塑性回升。随着热处理温度的增加，合金的硬度逐渐降低。同时发现保温时间对合金的硬度影响较大，随着保温时间的增加，合金的硬度下降。而冷却方式对合金的硬度影响不大。700℃热处理后合金拥有最高的硬度，为761HV。

关键词：多主元共晶合金；热处理；冷却方式；力学性能

Abstract：In this paper, the effects of heat treatment on the microstructure and properties of CoCrNiNb0.46 fully eutectic multicomponent alloys were studied. The samples were heat treated at 700, 800, 900 and 1000  ℃ for 24 hours and cooled in water. In addition, the   alloy at 1000  ℃ for 24 hours and then use the furnace cold, air-cooled treatment; 900  ℃ holding time extended to 48,72 hours heat treatment. The effects of different heat treatment processes on the microstructure and properties of CoCrNiNb0.46 alloy were investigated by   compression test, hardness test, SEM and XRD analysis. The results show that the microstructure of the alloy after 700  ℃ heat treatment has almost no change compared with the as-cast structure,which shows that the CoCrNiNb0.46 multi-element alloy with complete eutectic structure has good thermal stability. With the heat treatment temperature rising The eutectic microstructures began to appear when the temperature exceeded 900  ℃ , and the eutectic microstructure became serious after 1000 ℃ . After the alloy was heat treated at 1000 ℃ , the lamellar structure disappeared, and the Nb content in the alloy was almost the same. The Nb element exhibits an even distribution over the entire structure of the alloy. After the heat treatment of the alloy phase composition compared to the as-cast and almost no change, both by the FCC and Laves two-phase composition. The fraction of the FCC phase changes after the alloy is heat treated. The compressive strength of the heat treated alloy after the heat treatment is lower than that of the as-cast. 800 ℃ heat treatment of the alloy has the lowest compressive strength, 615MPa. The compressive strength of the alloy after 1000 ℃ furnace rises. As the heat treatment temperature increases, the hardness of the alloy gradually decreases. At the same time, it was found that the holding time had a great influence on the hardness of  the alloy, and the hardness of the alloy decreased with the increase of the holding time. While the cooling method has little effect on the hardness of the alloy. 700 ℃ heat treatment alloy has the highest hardness, 761HV.

Keywords: Multi-principal-element alloys; Heat treating; Cooling methods; Mechanical property

目录

第一章绪论 1

1.1引言 1

1.2多主元合金的定义 1