On Demand available April 26 - June 30, 2021 titanium, monocrystalline silicon, and polycrystalline graphite targets. The TiN interlayer was obtained by a reactive deposition process using argon Tribology and Mechanical Behavior of Coatings and and nitrogen gases. A polycrystalline graphite target was used to produce a Engineered Surfaces hydrogen-free amorphous carbon coating over the tailored interlayers. The coatings were deposited onto C17200 CuBe discs, and silicon wafers Room On Demand - Session E1 substrates. Instrumented indentation tests were carried out in a Bruker Friction, Wear, Lubrication Effects, and Modeling Ti950 Triboindenter to evaluate coating hardness and elastic modulus. Increasing load scratch tests, using a diamond Rockwell C tip in a Bruker E1-1 Multi-sensing Nano-wear with Electrical Contact Resistance and UMT-2 system, were conducted to evaluate coating adhesion to CuBe alloy Friction Measurement, Ben Beake ([email protected]), Micro substrate and measure friction coefficient and critical loads. Dry Materials Ltd, UK; T. Liskiewicz, Manchester Metropolitan University, UK; A. reciprocating ball-on-disk tribological tests were also conducted with this Harris, Micro Materials Ltd.; S. McMaster, A. Neville, University of Leeds, system, using two constant normal loads (10N and 20N) and a stroke of 4 UK mm. Scanning Electron Microscope (SEM), Raman spectroscopy and Wear begins at the asperities but typically the contact pressures acting on coherence correlation interferometry (CCI) were used to characterize the these are unknown in a standard macro-scale tribological test. In contrast, coatings and wear tracks after the tests. Results indicate that the Ti/TiN/Si testing at the nano-/micro-scale (“single asperity tribology”) enables the compound interlayer improved the adhesion of the a-C coating, showing onset of wear to be studied conveniently and correlations with friction higher critical failure loads compared to other combinations. Also, ball on forces investigated to aid the design of surfaces with improved wear disc tests indicate the formation of a transfer layer at the ball surface, resistance. promoting reduced wear and failure of the coating when in contact with Reciprocating contacts occur in a wide variety of practical wear situations AISI5200 steel balls. including hip joints and electrical contacts. In optimising materials for E1-3 Tribologically Enhanced Self-healing of Niobium Oxide Surfaces, improved durability in these contacts it is important that the contact Samir Aouadi ([email protected]), A. Shirani, J. Gu, B. Wei, D. conditions (e.g. sliding speed) can be reproduced. Hence, a capability for Berman, University of North Texas, USA rapid high-cycle linear reciprocating nano-scale wear tests has been Activating a self-healing process is a viable approach for preventing the developed (NanoTriboTest) with automatic recording of friction loops, failure of ceramics experiencing mechanically-induced crack propagation. cumulative energy dissipation and electrical contact resistance. The design Previously, it was demonstrated that niobium oxide (Nb2O5) exhibits self- has high level of lateral rigidity providing the necessary stability to perform healing properties activated by the formation of Nb-Ag-O ternary oxide nano- or micro-scale wear tests for extended duration (e.g. several hours, when heated above 945 °C in presence of silver. In this study, we explore up to 300 m sliding). the mechanism of lowering the high-temperature healing requirement by In this study, high cycle, up to 40 mm long track length reciprocating nano- assisting the process of crack repair with a normal load and shear stresses. wear tests have been performed on multilayer DLC coatings, and the Specifically, we propose to use tribologically-induced local heating as a biomedical alloys Ti6Al4V and 316L stainless steel. Stainless steel showed mechanism to enhance the self-healing ability of Nb2O5. During a pin-on- ductile response throughout the load range but an abrupt transition to disk test, whereby a niobium oxide flat was sliding against a silver-coated higher friction and fracture-dominated wear after ~20 cycles occurred on ball, a sudden lowering of the coefficient of friction was observed at Ti6Al4V. Friction and wear evolution in the test was compared to that in elevated temperatures (~600 °C). The better performance of the coating nano-fretting (gross slip) and nano-scratch (unidirectional) tests [1-3]. was associated with a surface reconstruction process initiated inside the Improved detection of the onset of wear and the subsequent failure wear track. Extensive characterization analysis of the wear track using mechanisms was achieved by a multi-sensing approach where changes to energy-dispersive x-ray spectroscopy, Raman spectroscopy, and x-ray electrical contact resistance were shown to correlate directly with the diffraction confirmed the presence of an Nb-Ag-O ternary oxide phase measured friction. Nano-wear tests of noble metal-noble metal contacts inside the wear track formed at elevated temperature. The formation of an (Au-Au and Ag-Ag) showed much longer endurance than gold vs. steel Nb-Ag-O ternary oxide at a much lower than thermodynamically-required contacts although occasional isolated failures were observed in 35000 cycle temperature suggests that the self-healing process can be initiated directly tests. during mechanically induced stresses. Such a process is a new recipe for improving wear and crack resistance characteristics of ceramic components [1] Short note on improved integration of mechanical testing in predictive and maybe tuned to provide the desired frictional response. wear models, TW Liskiewicz et al, Surf Coat Technol 237 (2013) 212. [2] Comparison of nano-fretting and nano-scratch tests on biomedical E1-4 Computer Simulations of FCC Alloys Subjected to Dry Sliding as Basis materials, BD Beake and TW Liskiewicz, Tribol Int 63 (2013) for a Near-Surface Deformation Mechanism Map, Stefan Eder ([email protected]), M. Rodríguez Ripoll, U. Cihak-Bayr, AC2T Research [3] Development of DLC coating architectures for demanding functional GmbH, Austria; D. Dini, Imperial College London, UK; C. Gachot, TU Wien, surface applications through nano- and micro-mechanical testing, BD Beake Austria et al, Surf Coat Technol 284 (2015) 334-343. We study the microstructural response of five FCC CuNi alloys subjected to E1-2 Interlayer Design to Increase Adhesion of a-C Coatings onto C17200 sliding with large-scale molecular dynamics simulations. The initial grains Copper-Beryllium Alloy Surface, Marcos Dantas dos Santos measure approximately 40 nm in diameter to ensure that plasticity is not ([email protected]), N. Fukumasu, Polytechnic School of the University of dominated by grain boundary sliding, so our polycrystalline aggregate Sao Paulo, Brazil; A. Tschiptschin, Metallurgical and Materials Engineering exhibits dislocation pile-up, twinning, and grain refinement analogous to Department, University of Sao Paulo, Sao Paulo, Brazil; R. de Souza, I. polycrystals with much larger grains. We analyze the depth-resolved time Machado, Polytechnic School of the University of Sao Paulo, Brazil development of the grain size, shear, twinning, and the stresses in the Copper-beryllium (CuBe) alloys are widely used in the aeronautic and aggregate to produce a deformation mechanism map for CuNi alloys. This automotive industries due to its good thermal properties and corrosion map captures the predominant microstructural phenomena occurring for a resistance. However, reduced hardness and wear resistance can limit the given composition and normal pressure, and will aid engineers in use in manufacturing applications. To overcome these limitations, hard optimizing materials/surfaces to work within a required operating range. ceramic coatings can be applied to the tool surface, increasing the wear We compare tomographic visualizations of our atomistic model with resistance, and reducing the friction coefficient. Among several coating focused ion beam images of the near-surface regions of real CuNi alloys options, amorphous carbon (a-C) coatings were selected in this work since that were subjected to similar loading conditions. this coating can present high hardness and a very low friction coefficient. E1-5 From Surface to Sub-surface Contributions to Friction at the Nevertheless, the main challenge in using a-C coatings onto CuBe alloys is Nanoscale, C. Menezes, UFSC, Brazil; V. Pavinato, L. Leidens, UCS - Caxias the low adhesion between copper and carbon. This work focused on the do Sul University, Brazil; F. Echeverrigaray, F. Alvarez, UNICAMP, Brazil; A. development of a complex interlayer to increase adhesion under high Michels, Carlos Figueroa ([email protected]), UCS - Caxias do Sul contact, pure sliding, and dry tribological conditions. Two interlayer University, Brazil compositions (Ti/Si and Ti/TiN/Si) were analyzed based on the improved The friction phenomenon is a complex manifestation of the nature bonding between copper and titanium, while the amorphous silicon layer originated in energy dissipation events owing to the lost work of non- was applied to reduce the diffusion of carbon into the titanium-based conservative forces. In spite of different surface mechanisms describing the layer. Pulsed Direct Current Magnetron Sputtering (pDCMS) system friction phenomenon at the nanoscale, the involved energy in such surface configuration was used to deposit the coatings using polycrystalline