Among different phases of alumina, corundum (α-Al2O3) is characterized by very high hardness (equal to 9 according to Mohs scale), high melting point (2044 °C), and different colors when impurities are present (sapphires, etc)., i.e., corundum is of interest for various applications.
The mechanical properties were assessed by nanoindentation and scratch tests, and the results showed lower elastic modulus values and equal or higher hardness values as compared to commercially used alloys, as well as high values for joint plastic deformation between the coating and substrate.
You are not hard for hardness's sake.
According to the characteristics of hardness-alternating formation, equal wear principle is adopted to design PDC bit.
The hardness of the film is equal to or higher than the substrate hardness.
The micro-hardness of substrate under the coating to a depth of 200 μm changes from 400 HV0.3 to an average hardness of the specimen material equal to 346 HV0.346
Silicon combines exceptional hardness with exceptional lightness — at an equal size a silicon case is half the weight of a titanium one and a quarter the weight of steel — but it can also be exceptionally brittle.
The reason for choosing acrylic plates instead of dentin specimen was to get an homogenous surface with the same hardness as dentin that would be equal for all the experiments.
This is in contrast to Tabor's classical result for hardness testing that has the normalized pressure solely equal to a constant when response is fully plastic.
In the optimum joining condition, welded joint with defect-free uniform microstructure, with strength equal to 98% of polyethylene and with higher elongation and hardness than the polyethylene was obtained.
