Ackland G J
School of Physics, The University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom.
Phys Rev Lett. 2006 Jul 7;97(1):015502. doi: 10.1103/PhysRevLett.97.015502. Epub 2006 Jul 6.
The iron-chromium alloy system has an unexplained anomaly: although there is a broad miscibility gap it appears to be favorable for chromium to dissolve in iron. This is consistent with ab initio calculation, but no simpler physically intuitive picture has been presented. Here it is shown that the Ising model, based on the bcc lattice with antiferromagnetic and ferromagnetic species, has the potential to exhibit similar behavior, with a skew miscibility gap arising from the solubility of antiferromagnetic species on nonadjacent sites. Essential characteristics of stainless steel (high Cr solubility and surface segregation) are correctly reproduced. Under some conditions, magnetization increases with temperature. The equilibrium miscibility gap due to mixed magnetism and segregation-driven positive dM/dT are fundamental features of the bcc Ising model itself, not just FeCr.
尽管存在一个宽泛的混溶间隙，但铬似乎有利于溶解在铁中。这与从头算计算结果一致，但尚未给出更简单的物理直观图像。本文表明，基于具有反铁磁和顺磁物种的体心立方晶格的伊辛模型，有可能表现出类似的行为，由于反铁磁物种在非相邻位点的溶解度而产生倾斜的混溶间隙。不锈钢的基本特性（高铬溶解度和表面偏析）得到了正确再现。在某些条件下，磁化强度随温度升高。由于混合磁性和偏析驱动的正dM/dT导致的平衡混溶间隙是体心立方伊辛模型本身的基本特征，而不仅仅是FeCr的特征。
