Fe—Mn—Cr合金晶间腐蚀电子理论研究

为了从电子层面揭示Fe—Mn—Cr合金晶间腐蚀的物理本质，采用递归法计算了合金的原子埋置能、格位能、亲和能等电子结构参数，探索合金晶间腐蚀机理。研究表明：Cr在晶内稳定性很低，Cr在晶界和表面稳定性较高，基体中的Cr首先扩散到晶界，并通过晶界扩散至合金的表面。Cr元素减小费米能级差，抑制合金的晶间腐蚀。O-Cr间的亲和能为负数，表明氧与Cr之间有相互作用，生成Cr的氧化物。当氧化膜达到一定厚度可起到保护合金的作用。碳与Cr的亲和能也为负数，且其数值比氧与Cr间的亲和能更负。合金中碳优先与Cr形成化合物，在晶界析出，造成晶界贫Cr，使合金晶间腐蚀加重。

The Electronic Theory Study on Intergranular Corrosion of Fe-- Mn-- Cr Alloy

In order to reveal the physical nature of intergranular corrosion of Fe--Mn--Cr alloy from electronic levels, the atomic embedded energy, lattice point energy, affinity energy and other electronic structure parameters have been calculated by using the recursive method, to explore the intergranular corrosion mechanism of alloy. Studies show that： Cr has very low stability in the grain, and has high stability in the grain boundary and surface, so Cr in matrix first spread to the grain boundaries and through the grain boundary diffuse to the alloy surface. Cr element can inhibit intergranular corrosion of the alloy by reducing the Fermi energy difference between grain and grain boundary. The affinity energy between O--Cr is negative, which indicates that the interaction between oxygen and Cr occurs, and Cr oxide is generated. When the oxide film reaches a certain level of thickness, it can play a role in protecting alloys. The affinity energy between C and Cr is also negative, and its value is more negative than that of the affinity energy between oxygen and Cr. Carbon with alloys combine with Cr forming compounds priority, and precipitates at the grain boundary, resulting in poor grain boundary Cr, which lead to intergranular corrosion of the alloy increase.