Abstract
A novel cyclic quenching (CQ) and austenite reverse transformation (ART) was proposed for a Fe-0.25C-3.98Mn-1.22Al-0.20Si-0.19Mo-0.03Nb (wt.%) Mo-Nb microalloyed medium-Mn TRIP steel to improve strength and ductility. The results show that after twice cyclic quenching and ART exhibited optimum comprehensive properties, characterized by an ultimate tensile strength of 838 MPa, a total elongation of 90.8%, a product of strength and elongation (PSE) of 76.1 GPa·%, and the volume fraction of austenite of approximately 62 vol.%.
Highlights
In order to meet the development trend of energy saving, consumption reduction, environmental protection and safety of automobiles, it is urgent to develop a new generation of advanced high-strength steels
Retained austenite is obtained by intercritical annealing, quenching-partitioning, reverse phase transformation annealing, etc., and the transformation induced plasticity (TRIP) effect produced by austenite deformation can significantly improve the overall mechanical properties of the steel [7,8,9]
A cyclic quenching and austenite reverse transformation (CQ-ART) process are proposed to obtain the high fraction of retained austenite in Nb-Mo microalloyed medium-Mn TRIP steel, and its mechanical properties and plasticizing mechanism are systematically analyzed
Summary
139-146 which hinders the transformation of RA into martensite under continuous strain conditions, resulting in poor mechanical properties. RA with low stability will be deformed immediately when it is subjected to small strain, resulting in unsustainable work hardening rate of medium Mn steel [10,11,12]. Obtaining RA with higher content and better stability is the key factor for the development of medium-Mn TRIP steel. Studying the reasonable ratio of multi-phase structure and its coordinated deformation during the deformation process is the key point of the induced phase transition. A cyclic quenching and austenite reverse transformation (CQ-ART) process are proposed to obtain the high fraction of retained austenite in Nb-Mo microalloyed medium-Mn TRIP steel, and its mechanical properties and plasticizing mechanism are systematically analyzed
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