Microstructure and Wear Behavior of High-Carbon Concentration CrCoNi Multi-principal Element Alloys

Author(s)

Bertoli, Gustavo ^[1] ; Koga, Guilherme Y. ^[2] ; Puosso, Fernanda C. ^[2] ; Clarke, Amy J. ^[3] ; Kiminami, Claudio S. ^[2] ; Coury, Francisco G. ^[2]

Affiliation

^[1] Univ Fed Sao Carlos, Grad Program Mat Sci & Engn, Rod Washington Luis, Km 235, BR-13565905 Sao Carlos, SP - Brazil

^[2] Univ Fed Sao Carlos, Dept Mat Sci & Engn, Rod Washington Luis, Km 235, BR-13565905 Sao Carlos, SP - Brazil

^[3] Colorado Sch Mines, George S Ansell Dept Met & Mat Engn, 1500 Illinois St, Golden, CO 80401 - USA

• Document type: Journal article
• Source: METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE; v. 52, n. 7, p. 3034-3050, JUL 2021.
• Web of Science Citations: 0

Abstract

CrCoNi multi-principal element alloys (MPEAs) have shown good strength-ductility combinations, but few other mechanical properties have been evaluated in these alloys so far. Although optimal wear-resistant alloys depend upon the intended application, a hard and tough material is often desirable. In this work, as-cast Cr40Co40Ni20 was tested for wear under dry-sliding conditions against an alumina pin, exhibiting good wear resistance and low coefficient of friction (CoF) of 0.12. To further improve the wear behavior, carbon (C) additions were evaluated in this alloy and in Cr40Co30Ni30, up to the liquid solubility limit at 1600 degrees C (similar to 24 at. pct C). Alloy design was performed using computational thermodynamic calculations. Predicted microstructures contain: self-lubricating graphite flakes, hard primary Cr-rich carbides, and a tough eutectic matrix; in good agreement with experimental results. As-cast Cr40Co40Ni20-C, even without microstructural refinement, displayed low specific wear rate (on the order of 10(-4) mm(3)/Nm) and moderate CoF (0.55-0.62). Its performance was hampered by the fracture and detachment of coarse primary carbides, which introduced an additional abrasive element into the tribosystem. These findings indicate that C additions to CrCoNi alloys, along with the refinement of primary carbides, represent a promising strategy to further improve the wear performance of MPEAs. (AU)

• FAPESP's process: 19/00229-4 - Phase equilibria and mechanical properties of a multicomponent medium entropy Cr40Co40Ni20 alloy
• Grantee: Gustavo Bertoli
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 19/21133-5 - Mechanical properties of multicomponent Cr40Co30Ni30 alloy produced by mechanical forming
• Grantee: Fernanda Cunha Puosso
• Support Opportunities: Scholarships in Brazil - Scientific Initiation