Question

The property due to which a material under stress deforms slowly but progressively over a period of time is called

Answer 1

The property due to which a material under stress deforms slowly but progressively over a period of time is called  creep or cold flow

Creep (sometimes called cold flow) is the property of a solid material to move slowly or deform permanently due to the effect of mechanical stresses in materials science. This can be the result of long-term contact of high levels of stress, which are still below the yield strength of the material.

Creep is more serious in those materials which are subjected to heat for long periods, and usually increases near their melting point.