阐述传统相变塑性(transformation induced plasticity,TRIP)钢在成分设计上存在的不足，利用偏聚热力学和动力学设计新型TRIP钢的成分.依据扩散动力学估算TRIP钢经亚临界区等温退火后的最慢冷速，取平衡计算和偏平衡所得T0温度的平均值作为过时效温度，依据Hillert模型估算贝氏体增碳所需时间，以上述估算所得的参数通过与大量实验室数据对比后均获证实.以热力学探讨TRIP钢热镀锌的条件，进行系列的焊接性能试验，并在上述基础上进行TRIP钢的大生产.以Dumay所提供参数，估算孪晶诱发塑性（twin induced plasticity,TWIP）钢中组元对奥氏体层错能（stacking fault energy,SFE）的影响，以及不同成分TWIP钢的层错能.根据形成六方马氏体所需层错能，设计TWIP钢的成分，经不同处理后获得应变诱发六方马氏体与淬火马氏体，探讨不同方法获得的马氏体对力学性能的影响.所设计钢经处理后，性能最佳者的抗拉强度达1 GPa，延伸率为60%，完全满足第三代汽车用钢的要求

The undesirable features in the composition design of traditional transformation induced plasticity （TRIP） steel are described, and composition of the new type TRIP steel is presented based on segregation thermodynamics and kinetics. The lowest cooling rate of steel after intercritical annealing is obtained with diffusion kinetics estimation. Overaging temperature is calculated from both equilibrium and paraequilibrium conditions. Carbon enrichment in Bainite is simulated, and the necessary time obtained based on the Hillert approximation. The calculated parameters are verified by comparison of calculation and experiment results. Conditions for hot dip galvanizing are discussed, and a series of welding tests carried out. The new steel is therefore massproduced in a large steel enterprise. Effects of elements on stacking fault energy (SFE) of austenite in twin induced plasticity (TWIP) steel are calculated. SFE in TWIP steels with different composition is estimated with the thermodynamic parameters proposed by Dumay. To obtain hexagonal close packed (HCP) martensite, composition of TWIP steel is also designed with special care in SFE. Functions of martensite obtained through different treatments on the mechanical properties are discussed, among which the best exhibits very good combination of strength and ductility, i.e., tensile strength over 1 GPa and elongation rate similar to 60%. This well meets the requirement of the 3rdgeneration automobile steel.