兼具高强塑积和高能量吸收能力的TWIP钢是最具应用潜力的新型汽车用钢，目前已获得较多的应用，如汽车防撞梁。然而到目前为止开发的TWIP钢通常表现出塑性有余而屈服强度不足的缺点。为弥补这一缺陷，本项目利用TWIP钢的变形机制受变形温度敏感影响的特点，提出通过调控预应变温度引入形变诱发孪生机制，使其与室温形变诱发ε马氏体相变异步协作的设计思路，开发以预应变控制为基础具有混合组织的新型高性能TWIP/TRIP钢。通过系统研究预应变工艺对微观变形组织的影响规律，考察预应变后室温成形过程中ε马氏体的形成演变规律以及其与预应变组织的交互作用，定量或半定量描述孪生/ε马氏体相变异步协作变形方式下流变应力与形变孪晶、ε马氏体及位错的关系，进而揭示孪生/ε马氏体相变异步协作变形机制及强韧化效果。本项目研究将丰富和发展金属材料塑性变形理论和强韧化理论，为新型高性能TWIP/TRIP钢的组织性能控制提供理论基。

TWIP steels with high strength-elongation product and high energy absorption capability offer the promising perspective for automotive industry and have been applied as structure parts, particularly in crash relevant parts. However, relatively low yield strength limits the further application. In order to circumvent this intractable issue, a research program is proposed based on the unique characteristic of deformation mechanisms depending on temperature in TWIP steels. The strategy is to introduce the deformation twin by controlling the pre-strain temperature. Upon that, asynchronous synergy of two deformation mechanisms, namely twinning and ε martensite transformation, will be developed in the material, leading to novel bimodal-microstructured TWIP/TRIP steels with high performance. By systematic research on the influence of pre-strain technology on microstructure, the formation process and the corresponding evolution mechanism of the ε martensite during plastic deformation at room temperature will be investigated, and the interactions of ε martensite with pre-strain deformation microstructures will be studied. The correlations between the flow stress of twinning/ε martensite transformation asynchronous deformation and the microstructures such as deformation twins, ε martensite and dislocations will be established quantitatively or semi-quantitatively. The mechanism of twinning/ε martensite transformation asynchronous deformation and the effective approach of strength-ductility will be revealed. Efforts of this study will provide a complement for not only the theory of plastic deformation but also the theory of strengthening and toughening, which serve as the theoretical guides for control of microstructure and performance for advanced TWIP/TRIP steels.