Research on the Microstructure and Microhardness of 9Cr18 Semi-Solid Billet

Abstract:

Formed in the semi-solid state, materials can obtain unconventional microstructures and properties compared with traditional method. In this paper, semi-solid billet of 9Cr18 steel was obtained through a wavelike sloping plate. Microstructure analysis of the semi-solid billet was conducted through scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). X-ray diffraction (XRD) test and microhardness test were also used to analyze the properties. The results showed that the structure of 9Cr18 semi-solid billet contained globular primary austenite and secondary austenite-Cr₇C₃ eutectic. Globular primary austenite grains were first formed during partial solidification in the sloping plate, and then the rest liquid metal formed secondary austenite and Cr₇C₃ eutectic structure surrounding the primary grains. Cr atoms had a concentration in the rest liquid side, which along with C atoms contributed to the formation of the Cr₇C₃ carbide. Hardness in the primary solid grain area and the eutectic area was about 330 HV and 650 HV, respectively. These specific properties were important for subsequent thixoforming of the functional graded materials.

• Periodical: Materials Science Forum (Volume 817)
• Pages: 278-282
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.817.278
• Online since: April 2015
• Authors: Yong Jin Wang*, Ren Bo Song, Ya Ping Li, Ruo Ling Bi
• Keywords: 9Cr18, Functionally Graded Material (FGM), Microstructure, Semi-Solid

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