What mechanical property measures a material's ability to resist scratches or dents?

The mechanical property that measures a material's ability to resist scratches or dents is indeed hardness. Hardness is a critical characteristic that indicates how well a material can withstand deformation, particularly from localized forces. It is often assessed through various tests, such as the Mohs scale for minerals or the Rockwell and Brinell tests for metals.

When a material has high hardness, it implies that it can endure external wear and abrasion better than softer materials. This property is particularly important in applications where surface integrity is crucial, such as tools, machinery components, and protective coatings.

Tensile strength relates to the maximum amount of tensile (stretching) stress a material can withstand before failure, which does not directly indicate its susceptibility to surface damage like scratches. Flexibility measures a material's ability to bend without breaking, while toughness assesses the ability to absorb energy and plastically deform without fracturing. While these properties are essential for different applications, they do not provide a direct measure of resistance to surface wear, which is the focus of hardness.