J. Mater. Sci. Technol. ›› 2021, Vol. 91: 200-214.DOI: 10.1016/j.jmst.2021.03.020

• Invited Review • Previous Articles     Next Articles

A review of the thermal stability of metastable austenite in steels: Martensite formation

Yong Lia, David San Martínb, Jinliang Wangc,a, Chenchong Wanga, Wei Xua,*()   

  1. aState key laboratory of rolling and automation, Northeastern University, Shenyang 110819, China
    bMateralia Research Group, Centro Nacional de Investigaciones Metalúrgicas (CENIM-CSIC), Avda Gregorio del Amo 8, Madrid E-28040, Spain
    cSchool of Mechanical and Power Engineering, Guangdong Ocean University, Zhanjiang 524088, China
  • Received:2020-12-17 Revised:2021-02-27 Accepted:2021-03-07 Published:2021-11-20 Online:2021-11-20
  • Contact: Wei Xu
  • About author:*E-mail address: xuwei@ral.neu.edu.cn (W. Xu).

Abstract:

Metastable austenite plays a critical role in achieving improved combinations of high strength and high ductility/toughness in the design of advanced high-strength steels (AHSS). The thermal stability of metastable austenite determines the transformation characteristics of AHSS and thus primarily determines the microstructure evolution during complex processes, e.g., the quenching and partitioning process, to achieve the desirable microstructure. This study provides a review of the thermal stability of austenite and its influence on martensitic transformation from both experimental and theoretical modeling perspectives. From the experimental perspective, factors affecting the thermal stability are analyzed, the relative sensitivities are compared, and their corresponding mechanisms are discussed. From the theoretical modeling perspective, the most representative kinetic models that describe athermal and isothermal martensitic transformation are reviewed. The advantages, shortcomings, and applicability of each model are discussed. The systematic review of both experimental and theoretical aspects reveals critical factors in tailoring the stability of metastable austenite and, therefore, provides guidance for the design of advanced steels.

Key words: Austenite, Thermal stability, Martensitic transformation, Kinetic models