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简介对 Fe—C、Fe—X 和 Fe—X—C 系马氏体相变热力学的处理方法和直接计算 M_S 所得的结果,对面心立方→体心立方(正方)马氏体相变热力学处理获得统一的概念,纠正 Fe—C 中微量碳剧烈降低 M_S 的不正确论点,论证 Fe—X 系中一些偏高的相变温度为 M_s 或表面马氏体的 M_S 温度,澄清了二十余年来对铁基合金相变驱动力错误和矛盾的说法。在合金钢(Fe—X—C 系)中,由碳在奥氏体的活度值可预测碳对 M_S 值下降的倾向。以钴及钴合金为例,述明面心立方→ε马氏体相变中,相变驱动力和层错能较大的金属可由极轴机制形核,相变驱动力很小的合金只能以层错直接形核。
Introduction Thermodynamic treatment of martensite transformations of Fe-C, Fe-X and Fe-X-C systems and calculation of M_S directly are carried out. A uniform concept was obtained to correct the incorrect argument that trace amounts of carbon in Fe-C drastically reduce M_S. Some high phase transition temperature in Fe-X system was demonstrated as M_s or surface martensite M_S temperature, clarifying more than 20 years To iron-based alloy phase change driving force wrong and contradictory statement. In alloy steel (Fe-X-C series), the activity of carbon in austenite predicts a decrease in the carbon-to-metal M_S value. Taking cobalt and cobalt alloys as an example, it is shown that in the face-centered cubic → ε-martensite phase transformation, the metal with larger phase-change driving force and stacking fault can be nucleated by the polar axis mechanism and the alloy with only a small driving force Stratification can be directly nucleated.