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Achieving Ultralow Wear with Stable Nanocrystalline Metals
Author(s) -
Curry John F.,
Babuska Tomas F.,
Furnish Timothy A.,
Lu Ping,
Adams David P.,
Kustas Andrew B.,
Nation Brendan L.,
Dugger Michael T.,
Chandross Michael,
Clark Blythe G.,
Boyce Brad L.,
Schuh Christopher A.,
Argibay Nicolas
Publication year - 2018
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201802026
Subject(s) - materials science , sapphire , nanocrystalline material , alloy , grain boundary , ceramic , delamination (geology) , composite material , metallurgy , nanotechnology , microstructure , paleontology , laser , physics , subduction , biology , optics , tectonics
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. Pt–Au, a proposed stable alloy consisting of two noble metals, is shown to exhibit extraordinary resistance to wear. Ultralow wear rates, less than a monolayer of material removed per sliding pass, are measured for Pt–Au 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 mm 3 N −1 m −1 , comparable to diamond‐like carbon (DLC) and sapphire. Remarkably, the wear rate of sapphire and silicon nitride probes used in wear experiments are either higher or comparable to that of the Pt–Au alloy, despite the substantially higher hardness of the ceramic probe materials. High‐resolution microscopy shows negligible surface microstructural evolution in the wear tracks after 100k sliding passes. Mitigation of fatigue‐driven delamination enables a transition to wear by atomic attrition, a regime previously limited to highly wear‐resistant materials such as DLC.