Microstructure-based constitutive model for static mechanical behavior of Si-Mn TRIP steels

Abstract

The need to improve formability and weight reduction in the automotive industry has greatly contributed to the development of transformation-induced plasticity (TRIP) steel. The stress–strain curves of TRIP steels can be generally controlled by adjusting composition, temperature and volume fractions. Based on Hollomon equation and mixture law, microstructure-based constitutive model of Si-Mn TRIP (transformation induced plasticity) steels in a static state was gained with experimental results through deriving steps “from ferrite and martensite to ferrite, martensite, and bainite, and finally to ferrite, martensite, bainite and austenite.” The simulation results were in good agreement with the experimental results. The true stress–strain curves of Si-Mn TRIP steels can be accurately predicted by computational method, which can be extended to more complex multicomponent alloy system. It can also be found that in TRIP steel, the strength of bainite and retained austenite are close.

Keywords:

• Constitutive model
• TRIP steel
• microstructure
• retained austenite