Achieving Ultralow Wear with Stable Nanocrystalline Metals

Journal Article · Mon Aug 06 00:00:00 EDT 2018 · Advanced Materials

DOI:https://doi.org/10.1002/adma.201870242· OSTI ID:1467025

Curry, John F. ^[1]; Babuska, Tomas F. ^[1]; Furnish, Timothy A. ^[1]; Lu, Ping ^[1]; Adams, David P. ^[1]; Kustas, Andrew B. ^[1]; Nation, Brendan L. ^[1]; Dugger, Michael T. ^[1]; Chandross, Michael ^[1]; Clark, Blythe G. ^[1]; Boyce, Brad L. ^[1]; Schuh, Christopher A. ^[2]; Argibay, Nicolas ^[1]

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1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Material, Physical, and Chemical Sciences Center
2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Materials Science and Engineering

Recent work suggests that thermally stable nanocrystallinity in metals is achievable in several binary alloys by modifying grain boundary energies via solute segregation. The remarkable thermal stability of these alloys has been demonstrated in recent reports, with many alloys exhibiting negligible grain growth during prolonged exposure to near-melting temperatures. In this paper, we show that PtAu, a proposed stable alloy consisting of two noble metals, exhibits extraordinary resistance to wear. Ultra-low wear rates, less than a monolayer of material removed per sliding pass, were measured for PtAu thin films at a maximum Hertz contact stress of up to 1.1 GPa. This is the first instance of an all-metallic material exhibiting a specific wear rate on the order of 10^-9 mm³/N-m, comparable to diamond-like carbon and sapphire. Remarkably, the wear rate of sapphire and silicon nitride probes used in wear experiments were either higher or comparable to that of the PtAu alloy, despite the substantially higher hardness of the ceramic probe materials. High-resolution microscopy showed negligible surface microstructural evolution in the wear tracks after 100k sliding passes. Finally, mitigation of fatigue-driven delamination enabled a transition to wear by atomic attrition, a regime previously limited to highly wear resistant materials such as diamond-like carbon.

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES); SNL Laboratory Directed Research and Development (LDRD) Program; US Army Research Office (ARO)
• Grant/Contract Number: NA0003525; W911NF-14-1-0539
• OSTI ID: 1467025
• Report Number(s): SAND2018-3274J; 661854
• Journal Information: Advanced Materials, Vol. 30, Issue 32; ISSN 0935-9648
• Publisher: Wiley
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
friction
metals
nanocrystalline
stable
wear