Fabrication and characterization of microstructure of stainless steel matrix composites containing up to 25 vol% NbC

Journal Article · Thu Sep 15 00:00:00 EDT 2016 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2016.07.019· OSTI ID:22689609

Ye, Zi Jie; Zhu, Yue ^[1]; Bhatia, Vijay Kumar ^[2]; Dolman, Kevin; Lucey, Timothy; Tang, Xinhu ^[3]; Proust, Gwénaëlle ^[1]; Cairney, Julie ^[2]

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1. School of Civil Engineering, The University of Sydney, NSW 2006 (Australia)
2. School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006 (Australia)
3. Weir Minerals Australia, Artarmon, NSW 2064 (Australia)

AISI 440 stainless steels reinforced with various volume fractions of niobium carbide (NbC) particles of up to 25 vol% were fabricated in-situ using an argon arc furnace and then heat-treated to produce a martensitic matrix. Optical and scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and electron back-scatter diffraction (EBSD) techniques were used to analyze the microstructure, phases and composition of these composites. Interestingly, it was found that Chinese-script NbC could nucleate on existing primary NbC particles creating NbC clusters with complex microstructures. Additionally, hardness tests were used to evaluate viability in mining and mineral processing applications. The increase in NbC content resulted in an overall increase in the hardness of the composites while causing a marginal decrease in the amount of Cr in solid solution with the matrix, which could be a concern for corrosion resistance. The latter was due to the fact that the NbC lattice could dissolve a minor amount of Cr. Thermodynamic simulations also attributed this to a slight increase in M{sub 7}C{sub 3} precipitation. Nonetheless, these novel composites show great promise for applications in wear and corrosive environments. - Highlights: •Stainless steels reinforced with NbC particles of up to 25 vol% were fabricated. •NbC was formed in-situ in the steels using an arc melter. •Martensitic transformation of the matrix of each sample was achieved. •NbC reinforcements increased the bulk hardness values of the steels. •Dissolved Cr in the matrix of each sample was sufficient for passivity in theory.

• OSTI ID: 22689609
• Journal Information: Materials Characterization, Vol. 119; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ARC FURNACES
ARGON
BACKSCATTERING
CHINA
CORROSION
CORROSION RESISTANCE
ELECTRON DIFFRACTION
FABRICATION
HARDNESS
HEAT TREATMENTS
MARTENSITIC STEELS
MATRICES
MICROSTRUCTURE
NIOBIUM CARBIDES
PHASE TRANSFORMATIONS
SCANNING ELECTRON MICROSCOPY
SOLID SOLUTIONS
STAINLESS STEELS
THERMODYNAMICS
X-RAY SPECTROSCOPY