Wear-Fatigue Behavior of Ni88P11.78Co0.12Fe0.10 and Ni80.55Cr15.25B4.20 Metallic Glasses During Rubbing Against an Eccentric Rotating Ceramic Roller

Abstract

The wear-fatigue rupture of Ni88P11.78Co0.12Fe0.10 (NiP) and Ni80.55Cr15.25B4.20 (NiCrB) glasses prepared by planar–flow casting have been studied using a test under simultaneous constant and cyclic loading generated by an eccentric rotation ceramic antagonist. For better apprehending the phenomena related to the structural state changes of samples before and after tests, structural characterization by x-ray diffraction, mechanical characterization by measuring Vickers microhardness (HV 0.1) and chemical composition by X-ray photoelectron spectroscopy (XPS) analysis have been carried out on as-quenched and worn dull side ribbons. Rupture surfaces, in S–N curves, have been measured by scanning electron microscope. Wear-fatigue contact tests consist to impose, simultaneously, a traction strain and cyclic normal stresses which generate traction, compression, rolling, bending and shearing. All results obtained from the two selected glasses (NiP and NiCrB) are systematically compared with those of a nickel pure crystalline foil (Ni). We evaluate mainly the wear mechanism, the mode and the typical rupture surface observed in NiP, NiCrB and Ni specimens. We specify the conditions of obtaining these rupture surfaces which often present in smooth plane, veining and “chevrons” patterns. All results show a great wear and fatigue resistance for the two metallic glasses compared to Ni. The NiCrB wear resistance is superior to that of NiP, while the difference in their fatigue limit is not clearly distinct. The reasons for the differences in wear and fatigue behavior will be discussed in relation to the metallic glass thermal stability, chemical composition, microhardness and surface rupture topography.