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Improved Mechanical Behavior and Plastic Deformation Capability of Ultrafine Grain Alumina Ceramics


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The nanoindentation and nanoscratch behavior under ramp loading conditions of three dense bulk alumina ceramic samples with average grain size regimes of ~290 nm, 750 nm, and 1.3 μm, respectively, has been investigated using a nanoindenter XPS system in indentation and scratch modes. The mechanical behavior, including hardness from nanoindentation tests, scratch hardness, scratch resistance, and coefficient of friction from nanoscratch tests, can be improved with grain refinement. Moreover, the surface roughness of the scratch grooves and the distinct morphologies of the nanoscratch debris from each sample reveal that alumina ceramic samples with ultrafine grain size exhibit an increase in plastic deformation capability at the nano- and micro-scale.