What is "toughness"?

Toughness refers to the ability of a material, particularly metals, to absorb energy and withstand sudden impacts without breaking. It is a measure of how much energy a material can take before fracturing. In contexts such as construction, manufacturing, or refrigeration systems, toughness is a critical property because materials often encounter unexpected stressors or forces that can lead to failure if the material is not tough enough.

When considering metals used in refrigeration applications, those that exhibit high toughness are particularly desirable due to their capacity to endure sudden changes in temperature and pressure, as well as shock loads that can occur during the operation of machinery. Thus, a tough metal will be more reliable and less likely to fracture under harsh operational conditions.

The other choices pertain to different material properties, such as stress resistance, indentation resistance, and elongation resistance, which are important factors in determining a material's overall usefulness, but do not specifically define toughness as it relates to impact resistance.