高Co-Ni二次硬化马氏体钢中合金元素对相变的影响

Effect of Alloying Elements on the Phase Transformation for Secondary Hardening Martensite Steels Enriched Co and Ni

利用“固体与分子经验电子理论”（ＥＥＴ）分析了高Ｃｏ－Ｎｉ二次硬化马氏体钢中几种主要合金元素在不同状态下的价电子结构，认为Ｃｏ、Ｎｉ在奥氏体中与Ｃ相互作用较强，它们能降低Ｃ的扩散能力，推迟马氏体相变。在马氏体回火过程中，Ｃｏ 和Ｎｉ溶入渗碳体形成的合金渗碳体，在较高的温度下分解，使固溶于基体中的Ｍｏ 与位错充分结合。在渗碳体分解后，Ｍｏ 与Ｃ形成富Ｃ、Ｍｏ的溶质簇，或以Ｍ２Ｃ的形式析出，在基体内弥散分布，形成二次硬化。

The empirical electron theory of solids and molecules (EET) has been applied to analyse the valence electron structure of major alloying elements for secondary hardening martensite steels enriched Co and Ni. The results show that interactions between Co (or Ni) and C are stronger, which result in reducing diffusibility of C in the austenite state and defening martensite transformation. The alloyed cementite melted into Co and Ni was decomposed in the higher temperature during martensite tempering, and they can conbine Mo atoms in the matrix with dislocations. After the cementite were resolved the solute clusters that enrich C, Mo and Cr were formed or M 2C was educed which dispersivily distributed in matrix and result in secondary hardening.