TiAl基合金的表面渗碳行为及其机理

Behavior and mechanism of TiAl based alloy surface carburization

测定了不同温度下TiAl基合金表面渗碳的动力学曲线,分析了表面渗碳层的结构和组成,研究了TiAl基合金的渗碳机理.结果表明,CO对具有不同扩散速率的Ti和Al进行的选择反应,导致渗碳层的多层结构;TiAl基合金的表面渗碳过程分为两个阶段:渗碳初期和渗碳稳定期.在渗碳初期遵守近似的抛物线增重规律,在渗碳稳定期遵守近似的直线增重规律;在渗碳稳定期,TiAl基合金的表面渗碳反应为零级反应,动力学行为遵守严格的线性变化规则;速率常数与温度的关系较好地遵守Arrhenius公式.

Mechanism of TiAl based alloy surface carburization was investigated based on the determination of the kinetics curves of TiAl based alloy surface carburization at different temperatures and the analysis of the microstructure and composition of the surface carburization layer. The results showed that choice reaction between carbon monoxide and Ti, Al elements was the prime mechanism for the formation of the carburization multi-layer structure. The surface carburization reaction of TiAl based alloy is zero order reaction, and the kinetics behavior of carburization obeys the rule of lineal change strictly. Variations of rate constant with carburization temperature agree with the Arrhenius formula.