Microstructure and Mechanical Properties of Medium Manganese Steel with Different Aluminum Addition After Very Short Time Intercritical Annealing

• Published in: Journal of materials engineering and performance Vol. 33; no. 4; pp. 2015 - 2026
• Main Authors: Ding, Wei, Zhang, Nan, Zhang, Guangying, Li, Yan, Zhang, Min
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-02-2024
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Corrosion and Coatings; Engineering Design; Materials Science; Quality Control; Reliability; Safety and Risk; Technical Article; Tribology; tensile properties; microstructure; aluminum; short intercritical annealing time; medium manganese steel
• ISSN: 1059-9495; 1544-1024
• DOI: 10.1007/s11665-023-08083-1

In this work, the phase transformation, microstructure, and mechanical properties of medium manganese steels containing 1.0 and 2.5% aluminum (mass%) were investigated at different intercritical annealing (IA) temperatures (670-820 °C) after very short IA times (1 min) using thermodynamic simulations, scanning electron microscopy, transmission electron microscopy, x-ray diffraction and uniaxial tensile tests. The results show that with the addition of aluminum, the temperature range between A
1
and A
3
increases from 338 °C for 1.0% Al to 506 °C for 2.5% Al. The retained austenite (RA) has two different morphologies, namely polygonal and lath. Most of the RA transformed into martensite during deformation. Two types of martensite were observed: the α’-martensite and ε-martensite. The steel with 2.5% aluminum (mass%), after IA at 790 °C, shows the best combination of tensile properties, including a tensile strength of 982.5 MPa, an elongation of 42.96%, and tensile strength × total elongation greater than 42 GPa%.