The Role of Transformation‐Induced Plasticity in the Development of Advanced High Strength Steels

Abstract

Lightweight structural components made of advanced high-strength steels (AHSSs) in the automotive industry can substantially reduce greenhouse gas emissions. The 3rd-generation AHSSs, which consist of medium Mn steel, quenching and partitioning (Q&P) steel, and carbide-free bainitic (CFB) steel, is the current research focus of the steel community. In particular, the retained austenite grains are the intrinsic components of the 3rd-generation AHSSs. These retained austenite grains can demonstrate a transformationinduced plasticity (TRIP) effect by transforming into martensite during mechanical loading, improving the strain-hardening behavior of AHSSs. Consequently, intensive research has been carried out over the past 30 years to understand the role of the TRIP effect on the development of AHSSs. Therefore, this review article is aimed to provide a state-of-the-art summary of recent progress on AHSSs with the TRIP effect. Specifically, the processing, the relationship between microstructure and mechanical properties, and the potential industrial applications of TRIP-enabled AHSSs will be addressed in this review. More importantly, the mechanical stability of the retained austenite grains, which determines the overall performance of the TRIP effect in AHSSs, will be discussed by considering several governing factors.

Deformation-induced Martensite Transformation Behavior during Tensile and Compressive Deformation in Low-alloy TRIP Steel Sheets

“…Representative 3rd generation steels, including quench and partitioning steel, 11,12) medium manganese steel, 13,14) carbide-free bainitic steel, 15,16) and TRIP-aided annealed martensitic steel, 17) include metastable γ and utilize the TRIP effect to improve performance. 18) Therefore, it is important to understand the transformation behavior of metastable γ during deformation in such steels.…”

On the Factors Governing Austenite Stability: Intrinsic versus Extrinsic

“…Moreover, the toughness and formability of steels can also be improved with the assistance of the TRIP effect [ 12 , 13 , 14 , 15 ]. This TRIP effect plays a pivotal role in developing the advanced high strength steels (AHSSs) [ 16 ], including the TRIP-assisted steel [ 17 ], maraging TRIP steel [ 18 ], medium Mn TRIP steels [ 19 , 20 ], quenching and partitioning (Q&P) steels [ 21 , 22 ], and carbide free bainite (CFB) steels [ 23 ]. Austenite is the common phase in the above AHSS and is the source of the TRIP effect.…”

On the Variants of Thermal Process in Developing Strong and Ductile Medium Mn Steel

“…High-performance steels are desirable to develop lightweight structural components with high safety coefficient in various areas, such as automotive and aerospace. Medium manganese steels are supposed to be a promising candidate of the third generation advanced high-strength steels (AHSS) because of their good mechanical properties, which is ascribed to martensitic transformation during plastic deformation (He et al, 2017;Hu et al, 2017;Liu et al, 2018). Generally, the medium Mn steel is processed by intercritical annealing (IA) to achieve a dual-phase microstructure consisting of ferrite and retained austenite (γ R ) (Lee and De Cooman, 2014;Wang H. et al, 2018;Chandan et al, 2019).…”