Environment-Dependent Tribological Properties of Bulk Metallic Glasses
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ORIGINAL PAPER
Environment‑Dependent Tribological Properties of Bulk Metallic Glasses Morgan R. Jones1 · Andrew B. Kustas1 · Ping Lu1 · Michael Chandross1 · Nicolas Argibay1 Received: 17 August 2020 / Accepted: 22 October 2020 © This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply 2020
Abstract The macroscale friction and wear properties of the Z r44Cu10Ni10Ti11Be25 metallic glass were investigated as a function of environmental oxygen concentration and contact force. We found remarkably low and predictable friction when both oxidation and frictional heating (that can lead to thermomechanically-driven crystallization) were supressed. Conversely, oxidation and the formation of a mixed metal-oxide layer was shown to increase the friction coefficient while significantly reducing wear rates. Depending on conditions, the wear rates ranged from values comparable to highly wear-resistant materials like polymer and 2D solid lubricant nanocomposites to those that are found with soft, pure, high-wear metals. These results reveal that the competition between material removal and the deformation-induced mixing of oxide particles can dramatically reduce wear rates, suggesting opportunities for optimization of tribological performance. Keywords Bulk metallic glasses · Amorphous metals · Tribology · Friction · Wear · Oxidation
1 Introduction Since the first report of low friction and high hardness of Ni- and Fe-based metallic glass (MG) ribbons in 1980 [1], the tribological properties and deformation mechanisms of MGs have been the focus of many investigations [2–20]. The amorphous structure of these alloys imparts many desirable properties, including superplasticity [21–23], high fracture toughness [24–26], and record-setting strength [26–30]. Unlike crystalline metals, where strength is often dependent on dislocation nucleation and motion, amorphous metals accommodate plastic deformation by shear banding (inhomogeneous deformation) at lower temperatures and higher strain rates, or by processes like viscous flow (homogeneous deformation) at higher temperatures and lower strain rates [27]. A mechanistic understanding of the strength and deformation of metallic glasses (MGs) remains a topic of active research [3, 31–34] because of the potential application of these materials in many engineering applications, such as lightweight structural members for automobiles and aircrafts. Here we present an investigation of the tribological * Nicolas Argibay [email protected] 1
Material, Physical, and Chemical Sciences Center, Sandia National Laboratories, Albuquerque, NM 87123, USA
properties of metallic glasses, and show that, in the absence of confounding effects from environment and frictional heating, friction coefficients can be directly linked to fundamental mechanisms of deformation. This investigation specifically focuses on the friction and wear properties of a commercially-available MG, Zr44Cu10Ni10Ti11Be25 (Vitreloy 1b), similar in composition and ther mom
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