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Nb/Nb5Si3原位复合材料极具替代现有镍基超合金作为未来飞行器发动机超高温部件材料的潜力。本研究采用反应热压烧结、反应放电等离子烧结等粉末冶金技术及氩弧熔炼技术制备了多种成分的Nb/Nb5Si3原位复合材料 ,并对其组织形态、高温强度及室温塑性进行了考察。结果表明 :两种粉末法制得的复合材料具有类似的显微组织 ,即Nb固溶体与硅化物两相均呈现等轴状晶粒分布。合金元素Mo、W对烧结组织形貌无明显影响 ,但可改变凝固过程Nb5Si3的析出机制 ,从而优化氩弧熔炼合金的组织形态。粉末合金保持较高高温强度 ,并具有较高室温塑性。熔炼材料的高温强度远高于粉末合金 ,其中Nb 16Si 10Mo 15W合金 16 0 0℃时的压缩屈服强度高达50 0MPa。
The Nb / Nb5Si3 in-situ composites greatly replace the existing nickel-based superalloys as potential materials for future ultra-high temperature parts of aircraft engines. In this study, Nb / Nb5Si3 in-situ composites with various compositions were prepared by powder metallurgy, such as reactive hot-press sintering, reactive discharge plasma sintering and argon arc melting. The microstructure, high temperature strength and room temperature plasticity were investigated. The results show that the composite obtained by the two powder methods has a similar microstructure, that is, the equiaxed grain distribution of both Nb solid solution and silicide appears. Alloying elements Mo, W have no obvious effect on the morphology of the sintered microstructure, but can change the precipitation mechanism of Nb5Si3 in the solidification process and optimize the microstructure of the alloy. Powder alloy to maintain high temperature strength, and has high room temperature plasticity. The high-temperature strength of smelting material is much higher than that of powder alloy. The compressive yield strength of Nb 16Si 10Mo 15W alloy at 600 ℃ is as high as 50 0MPa.