Which property typically indicates a material's resistance to deformation under load?

Hardness is indeed the property that typically indicates a material's resistance to deformation under load. It measures how well a material can withstand mechanical forces, including indentation, scratching, or penetration. In practical terms, a harder material can resist the introduction of a shape change when a load is applied, making it valuable in applications where surface integrity is crucial.

For example, if you consider different materials like metals, ceramics, and polymers, those that exhibit higher hardness values will generally show greater resistance to deformation. This is particularly important in engineering and manufacturing, where materials are often required to maintain their shape and structural integrity under various types of stress and load during their use.

While other properties like elasticity, ductility, and toughness are important for understanding material behavior, they relate to different aspects of material performance. Elasticity pertains to a material's ability to return to its original shape after the load is removed, ductility measures how much a material can stretch before breaking, and toughness encompasses a material's ability to absorb energy and deform plastically without fracturing. Each of these properties plays a role in material selection based on the intended application, but hardness is uniquely focused on resistance to deformation under load.