Influence of nitrogen and carbon addition on the mechanical properties of medium manganese steels

• Grant number: 23/17745-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2024
• End date: April 30, 2025
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal Investigator: Lucas Barcelos Otani
• Grantee: João Gabriel Stefanini Braga
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

The advanced high-strength steels are alloys developed with the aim of increasing the mechanical strength of steels to achieve greater structural efficiency. One of the main classes of next-generation steels being developed is medium manganese steels. Their excellent properties arise from obtaining an austenitic microstructure in which induced plasticity phenomena can occur. Additions of interstitial elements not only tend to increase the values of stacking fault energy (SFE), but it has also been described that additions of carbon can lead to an increase in the strain-hardening capacity of medium manganese steels. It is believed that a similar effect may be observed with nitrogen additions. Therefore, the objective of this project is to investigate the effect of N and C additions on the mechanical behavior of medium manganese steels. Initially, calculations will be performed to determine a composition range where the austenitic phase is expected. Models will be applied to estimate the SFE values as a function of composition, and these calculations will be done for different levels of interstitial elements. Two medium manganese steels will be processed with different N and C contents. The alloys will be melted, mechanically processed, and heat-treated to ensure a microstructure with equivalent grain sizes. Mechanical characterization will be performed through uniaxial tensile testing, and correlations with the predicted SFE values from thermodynamic models will be made based on the obtained mechanical properties.