An Assessment and Utilization of Thermodynamic Parameters of Al-Containing Advanced High Strength Steels

Abstract:

To predict phase equilibria of advanced high strength steels accurately, a new multicomponent thermodynamic database (FEDA) encompassing Fe, C, Mn, Si, Al and Ni is created according to relevant literatures. This study applies Thermo-Calc software to estimate phase transformation temperatures and phase fractions in ferrite and austenite two-phase region of test steels. Simultaneously, experiments are carried out with dilatometer and the quantitative metallographic analysis technology. It is found that the FEDA database is appropriate for predicting A₁ temperature and phase fractions of Al-containing steels at low temperatures, while the TCFE6 database can be used to estimate A₃ temperature. According to calculated phase fractions using FEDA database, a two-step heat treatment is made in order to achieve TRIP-aided steels. Samples annealed at 780°C for 3 min and held at 420°C for 5 min exhibit an optimum value of strength and ductility product up to 23690 MPa·%.

• Periodical: Advanced Materials Research (Volume 710)
• Pages: 55-59
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.710.55
• Online since: June 2013
• Authors: Wei Sen Zheng, Yan Lin He, Xiao Gang Lu, Lin Li
• Keywords: Al-Containing AHSS, Fe-Al-C System, Phase Fraction, Thermodynamic Parameter, Transformation Temperature

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