What term describes the ability of alloy steels to retain hardness at high temperatures?

The term that describes the ability of alloy steels to retain hardness at high temperatures is red-hardness. This property is particularly important for tools and components that are subjected to high temperatures during operation, such as cutting tools. Red-hardness allows these materials to maintain their hardness and cutting efficiency even when heated, which can occur due to friction or the heat generated during machining processes.

Ductility refers to a material's ability to deform under tensile stress, which is not specifically related to high-temperature hardness. Austenitic describes a specific phase of steel and its structure, commonly seen in alloy steels, but does not directly relate to maintaining hardness at elevated temperatures. Carburization involves the process of adding carbon to the surface of steel to increase its hardness and wear resistance, but it does not specifically pertain to the retention of hardness at elevated temperatures. Thus, red-hardness is the most accurate term for the question posed.