针对中锰钢奥氏体中形成的Mn化学界面，基于晶体塑性理论框架，建立了考虑位错密度演化及形变诱导相变的晶体塑性模型，研究了单一奥氏体晶粒内部存在化学界面情况下的微观变形行为，获得了奥氏体晶粒内部应力、应变及位错密度的分布，以及变形过程中形变诱导相变分数的演化。结果显示，奥氏体中化学界面的存在不仅能引起晶粒内部的应力与应变产生微区配分，即富Mn侧奥氏体承载更多的应力，贫Mn侧奥氏体承载更多的应变，而且会使同一个奥氏体晶粒内部各处的机械稳定性呈现差异性分布，使奥氏体在变形过程中渐次地发生相变诱导塑性(TRIP)效应，从而提高材料的强度和塑性。

Chemical boundaries (CBs) delineate two areas within a continuous lattice that have same structures but exhibit a sharp chemical discontinuity. CBs can be seen as a unique planar defect that is distinct in certain aspects from traditional physical interfaces such as phase boundaries and grain boundaries (GBs). Recently, GBs have been established within the austenite of medium Mn steels; they have been proven to substantially enhance the stability of austenite. This allows austenite to be easily retained at room temperature and offers additional possibilities for managing its mechanical stability. In this study, a crystal plasticity modeling was performed to simulate the deformation behavior of austenite containing a CB. First, an extended dislocation-based crystal plastic model that incorporates the deformation-induced martensitic transformation and stacking fault energy was developed. The inverse Nishiyama-Wassermann (N-W) relation was used to accurately describe the orientation relationship between austenite and newly formed martensite. The Mn content on both sides of the CB is taken as a state variable to calculate the stacking fault energy. This leads to varying responses in the deformation-induced martensitic transformation and dislocation slip within a single austenite grain. Results reveal a strain incompatibility between Mn-rich and Mn-poor austenite that causes a geometrically necessary dislocation to accumulate near the CB. Furthermore, the deformation-induced martensitic transformation on both sides of the CB behaves differently, leading to a “spectral” distribution of mechanical stability within a single austenite grain. This heterogeneity in the mechanical stability of austenite is highly beneficial. It allows a gradual deformation-induced phase transformation throughout the entire deformation process, which is crucial for enhancing the strength and plasticity of transformation induced plasticity (TRIP)-aided steels simultaneously.