Stress relaxation is creep related phenomenon:

Problem:

What is stress relaxation? Give example.

Solution

Stress relaxation is creep related phenomenon. It is loss of stress in a part under constant strain over a given period of time at elevated temperature.

For examples bolts are tightened to a fixed strain and stress to keep the cover of a pressure vessel leak proof. If the pressure vessel is used at high temperature the stress in bolts will reduce whereas the bolts will not lose their extension.