TY - JOUR
T1 - Microstructure characterisation and mechanical properties of a functionally-graded NbC/high chromium white cast iron composite
AU - Kan, Wen Hao
AU - Albino, Carlos
AU - Dias-da-Costa, Daniel
AU - Dolman, Kevin
AU - Lucey, Timothy
AU - Tang, Xinhu
AU - Chang, Li
AU - Proust, Gwénaëlle
AU - Cairney, Julie
PY - 2018/2
Y1 - 2018/2
N2 - A functionally graded NbC – high chromium white cast iron composite was successfully fabricated by centrifugal casting for high wear applications. The migration of primary NbC particles to the outer periphery, as predicted by Stokes’ law, resulted in an extremely hard outer layer at the surface of a softer bulk material. Microstructural characterisation showed that both the volume fraction and the morphology of the carbides varies along the thickness of the specimen. At the outer surface, the NbC was present as primary carbides while Chinese-script NbC was found in the bulk of the material. Hardness, sliding wear and three-point bending tests confirmed that the outer layer was harder and more wear resistant than the rest of the material, which was correspondingly tougher. The study of the fracture surface of the specimens showed that there is a strong bond between NbC and the matrix such that delamination between the reinforcements and the matrix did not occur during fracture. If Chinese-script NbC can be reduced or prevented in the bulk material, further improvements to toughness could be achieved.
AB - A functionally graded NbC – high chromium white cast iron composite was successfully fabricated by centrifugal casting for high wear applications. The migration of primary NbC particles to the outer periphery, as predicted by Stokes’ law, resulted in an extremely hard outer layer at the surface of a softer bulk material. Microstructural characterisation showed that both the volume fraction and the morphology of the carbides varies along the thickness of the specimen. At the outer surface, the NbC was present as primary carbides while Chinese-script NbC was found in the bulk of the material. Hardness, sliding wear and three-point bending tests confirmed that the outer layer was harder and more wear resistant than the rest of the material, which was correspondingly tougher. The study of the fracture surface of the specimens showed that there is a strong bond between NbC and the matrix such that delamination between the reinforcements and the matrix did not occur during fracture. If Chinese-script NbC can be reduced or prevented in the bulk material, further improvements to toughness could be achieved.
KW - Functionally-graded material
KW - High chromium white cast iron
KW - Metal matrix composite
KW - Microstructure
KW - Niobium carbide
KW - Wear
UR - http://www.scopus.com/inward/record.url?scp=85038096662&partnerID=8YFLogxK
U2 - 10.1016/j.matchar.2017.12.020
DO - 10.1016/j.matchar.2017.12.020
M3 - Article
AN - SCOPUS:85038096662
VL - 136
SP - 196
EP - 205
JO - Materials Characterization
JF - Materials Characterization
SN - 1044-5803
ER -