Strong grain-size effect on martensitic transformation in high-carbon steels made by powder metallurgy

• DOI: 10.1016/j.powtec.2020.01.002
• Publication Date: 2020-01-07T06:56:29Z
• Authors: Tao Jiang; Junjie Sun; Yingjun Wang; Hongji Liu; Shengwu Guo; Wenqing Liu; Yongning Liu
• Keywords: Powder Metallurgy; Diffusionless transformation; Volume fraction; Carbon fibers

Abstract The effect of prior austenite grain size on martensitic transformation has been studied in a high‑carbon steel with the composition of 1.0C-1.5Cr-0.3Mn-0.3Si-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 (PAGS) is reduced to about 3 μm. Furthermore, besides film-like retained austenite, blocky retained austenite is also observed with a total volume fraction of more than 30% when PAGS reaches 0.54 μm.