Red Seal Tool and Die Maker Practice Exam

What is the term for the ability of a material to deform under stress without breaking?

1. Strength

2. Toughness

3. Ductility

4. Hardness

The correct answer is: Ductility

The ability of a material to deform under stress without breaking is referred to as ductility. Ductility is a key property that indicates how much a material can stretch or change shape when subjected to tensile forces before failing. This characteristic is particularly important in applications where components are subject to bending or stretching, as it allows for energy absorption and helps prevent sudden failure. Ductility is often quantified by measuring how far a material can be pulled before it fractures, typically expressed in terms of elongation or reduction of area. Materials with high ductility can undergo significant plastic deformation, allowing them to adapt to stresses instead of breaking immediately. In contrast, strength refers to the maximum stress a material can withstand without failure, toughness describes a material's ability to absorb energy and plastically deform without fracturing, and hardness measures a material's resistance to deformation, particularly by indentation. Each of these properties serves a different purpose in material applications, but in this context, ductility specifically captures the idea of deformation under stress.