Powder Technology, Vol.363, 652-656, 2020
Strong grain-size effect on martensitic transformation in high-carbon steels made by powder metallurgy
The effect of prior austenite grain size on martensitic transformation has been studied in a high-carbon steel with the composition of I.0C-1.5Cr-0.3Mn-O.3Si-Fe (wt). Powder metallurgy was used to obtain different grain-sized samples given its high performance to resist grain growth during austenitization. It is found that transformation twin is suppressed and replaced by dislocation martensite when the prior austenite grain size (PACS) is reduced W about 3 um. Furthermore, besides film-like retained austenite, blocky retained austenite is also observed with a total volume fraction of more than 30' when FAGS reaches 054 Lim, (C) 2020 Elsevier B.V. All rights reserved.
Keywords:Grain site effect;Martensitic phase transformation;High-carbon steels;Powder metallurgy;Twinning