原位生成NbC/Fe复合材料反应过程及热力学分析
Analysis on Reaction Process and Thermo-dynamics of In-situ NbC/Fe Composite
王娜娜, 许云华, 刘晓洁, 钟黎声
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作者单位：(西安建筑科技大学 机电工程学院 耐磨材料研究所, 陕西 西安 710055)
中文关键字：原位生成； NbC； 复合材料； 热力学计算
英文关键字：in-situ synthesis; NbC; composite; thermo-dynamics calculation
中文摘要：利用铸造复合-热处理技术原位合成了NbC颗粒增强铁基复合材料，在分析DSC的基础上初步确定了实验所采取的热处理温度，探讨了其反应过程。采用XRD、SEM等检测手段对复合材料的相组成和显微组织进行了观察，最后应用热力学理论对在该工艺条件下原位合成NbC增强颗粒的可行性进行了计算验证。研究结果表明：在Fe-Nb-C三元体系中，其原位反应动力学过程为：738 ℃时铁素体晶界开始熔化消失；814 ℃时为α-Fe转变为γ-Fe的转变温度；1172 ℃为体系发生共晶反应的温度：L?邛NbC + γ + G；在1280 ℃时析出了一次碳化物NbC；在1172 ℃时，NbC优于其他相生成且属于热力学稳定相。
英文摘要：An iron matrix composite reinforced with NbC particle was prepared by in-situ synthesized process through casting and heat treatment technology. The heat treatment temperature was determined based on the analysis of DSC and the reaction mechanism was discussed. The microstructure was examined and analyzed by XRD and SEM. Finally, the feasibility of in-situ synthesized NbC particle was verified by thermo-dynamic theory. The experiment results show that, in the Fe-Nb-C ternary system, the kinetics reaction process during the in-situ reaction is like this, the ferrite crystal boundaries begin to melt away at 738 ℃: the ferrite transforms into austenite at 814 ℃; the eutectic reaction of the system (L?邛NbC + γ + G) begins at 1172 ℃; the first NbC precipitates at 1280 ℃; NbC particle is a thermo-dynamic stable phase and forms prior to other phases at 1172 ℃