Which property refers to a material's ability to resist penetration?

The property that refers to a material's ability to resist penetration is hardness. Hardness is a measure of a material's resistance to deformation, particularly permanent deformation, scratching, or penetration. It indicates how well a material can withstand applied force without yielding or being penetrated by a harder object.

In practical terms, harder materials are typically used in applications where durability and wear resistance are critical, such as cutting tools or industrial machinery components. The testing methods for hardness, such as the Rockwell or Brinell tests, quantify this ability by applying a specific force with a standardized indenter and measuring the resulting depth or diameter of the indentation.

Understanding hardness is essential for materials selection in engineering applications, as it affects not only performance but also longevity and maintenance requirements in various environments.