摘要
利用固体与分子经验电子理论建立了团球γ-(Fe,Mn)3C共晶体增强奥氏体γ钢基自生复合材料(EAMC)初生奥氏体枝晶的价电子结构.在提出晶胞对溶质原子的"键约束因子"δi概念的基础上,结合元素平衡分配系数k0的统计物理定义,得出δi愈大,原子固相位垒QS愈大,则原子愈容易由固液界面向液相扩散,k0增大;反之,k0减小的观点.据此解释了Si促进EAMC凝固过程中C、Mn元素(k0<1)枝晶偏析的原因:Si的加入使EAMC初生奥氏体枝晶中δC、δMn较小的γ-Fe-C-Si与γ-Fe-C-Mn-Si晶胞的相对数量增加,δC、δMn较大的γ-Fe-C-Mn晶胞减少,降低了C、Mn元素的QS.
The valence electron structure of the primary austenite dendrite in an in-situ γ-(Fe,Mn)3C eutectic reinforced austenite steel matrix composites (EAMC) was established by using the empirical electron theory of solids and molecules. Bond restriction factor (δi), as the restriction force of a cell on the solute atom, was defined. Based on the discussion on the statistic physics definition of equilibrium partition ratio (k0), it can be concluded that the higher δi, the higher solid energy barrier of the atom (Qs), the easier diffusion of the atom from the solid/liquid (S/L) interface to the liquid, the higher k0, otherwise, k0 decreases. The amounts of γ-Fe-C-Si and γ-Fe-C-Mn-Si cells increase in which bond restriction factors of C and Mn atoms are larger, but that of 7-Fe-C-Mn cells decrease in which bond restriction factors of the C and Mn atoms are smaller with the addition of Si. Accordingly, Qs of C and Mn decreases, and k0 decreases. It indicates that the segregation of C and Mn increases.
出处
《上海交通大学学报》
EI
CAS
CSCD
北大核心
2005年第1期18-22,共5页
Journal of Shanghai Jiaotong University
基金
国家自然科学基金资助项目(50001008
50271042)
关键词
奥氏体
共晶体
自生复合材料
偏析
价电子
Austenite
Carbon
Eutectics
Manganese
Metallic matrix composites
Metallography
Silicon
