Effects of Strain-Rate and Deformation Mode on Strain-Induced Martensite Transformation of AISI 304L Steel Sheet
Metastable austenitic stainless steels are prone to strain-induced martensitic transformation (SIMT) during deformation at room temperature, as in the case of sheet metal forming processes. SIMT is influenced by chemical composition, grain size, temperature, deformation mode or stress state and strain-rate effects. In this work, uniaxial and plane-strain tension tests were performed in AISI 304L sheet to evaluate the SIMT as a function of strain-rate. Feritscope and temperature in-situ measurements were performed during the uniaxial tensile testing. Digital image correlation (DIC) technique was employed to determine the in-plane surface strains of the plane-strain tension specimen. From the uniaxial tensile and plane-strain tension results, the yield stress increased with the strain-rate in the small strain range whereas a cross-effect in the stress-strain curve is exhibited in the large strain domain. This effect is attributed to the specimen heat generation, which inhibits the SIMT phenomenon. Conversely, plane-strain deformation mode displayed a higher SIMT rate and an improved work-hardening behavior in comparison to the uniaxial tensile straining.
Prof. Jongwan Hu
A. de Melo Pereira et al., "Effects of Strain-Rate and Deformation Mode on Strain-Induced Martensite Transformation of AISI 304L Steel Sheet", Applied Mechanics and Materials, Vol. 835, pp. 216-221, 2016