Which characteristic refers to a material's ability to endure pressure and not yield?

• A. Hardness
• B. Density
• C. Toughness
• D. Brittleness

Answer: (C)

The characteristic that refers to a material's ability to endure pressure and not yield is toughness. Toughness is the measure of a material's resistance to fracture when stressed. It reflects the capacity of a material to absorb energy and plastically deform without breaking. This property is particularly important in aviation applications, where materials must withstand significant stress and potential impacts without failing.

In contrast, while hardness measures a material’s resistance to deformation, it does not necessarily indicate its ability to absorb energy without cracking. Density refers to the mass per unit volume of a material and does not directly relate to its strength or durability under pressure. Brittleness describes materials that tend to fracture or break with little to no plastic deformation when subjected to stress, which is the opposite of the desired property of toughness. Thus, toughness is indeed the correct answer, as it embodies the ability to resist yield under pressure.