The present work deals with achieving improvement in the mechanical properties of SUS304L stainless steel through the application of a unique microstructure design termed as 'Harmonic structure', and establishing a co-relationship between various microstructural characteristics and mechanical properties. Harmonic structure essentially means a bimodal grain size distribution with a specific periodic arrangement of coarse- and ultrafine-grain fractions. SUS304L stainless steel samples having such microstructure were fabricated by a powder metallurgy route involving the mechanical milling of pre-alloyed steel powder followed by spark plasma sintering. Due to these peculiar microstructural characteristics, the harmonic-structured SUS304L stainless steels demonstrated a winning combination of high strength, large uniform elongation, and large total elongation to failure, simultaneously. It was also found that the fraction of a shell area (a three-dimensional continuously connected network of ultrafine-grained structure) is an important parameter controlling the balance of the mechanical properties of the harmonic-structured SUS304L steel compacts. © 2014 Elsevier B.V.
Zhang, Z., Vajpai, S. K., Orlov, D., & Ameyama, K. (2014). Improvement of mechanical properties in SUS304L steel through the control of bimodal microstructure characteristics. Materials Science and Engineering A, 598, 106–113. https://doi.org/10.1016/j.msea.2014.01.023