面心立方Fe中合金元素偏析行为的理论研究

Theoretical study on segregation behavior of elements in FCC Fe alloy

合金元素偏析对金属力学性能有很大影响,为研究偏析产生的机理以及抑制偏析的产生,采用基于密度泛函理论的第一性原理计算常见合金元素Ni、Cu、Cr、Mo、Mn在层错区的偏析情况,分析La对抑制偏析的作用。结果表明:Mo在层错区的有效能、偏聚能、层错能、态密度均很小,易在层错区发生偏析;掺入La后能提高层错区Mo原子的有效能、偏聚能、层错能和态密度,因此La有助于抑制Mo在层错区的偏析。

The segregation behavior of alloying elements has a great influence on the mechanical properties of metals. In order to study the mechanism of segregation and restrain the generation of segregation,the segregation behavior of Ni,Cu,Cr,Mo,Mn elements in the stacking fault region were simulated by using first-principles based on density functional theory(DFT),and the inhibition effect of La element on the segregation behavior was also analyzed. The results reveal that Mo is easy to segregate in the stacking fault area because of the low effective energy,segregation energy,stacking fault energy and density of states.However,the addition of La element can increase effective energy,segregation energy,stacking fault energy and density of states of Mo in the stacking fault region. Therefore,La element is beneficial to restrain the segregation behavior of Mo in the stacking fault region.