The influence of stress on the oxidation of a Ni-based superalloy

•External chromia thickness was unaffected by stress.•Tensile stress resulted in increase of alumina penetration by factor of 2.•This is taken to be evidence of Stress Aided Grain Boundary Oxidation (SAGBO).•Tensile stress at the tip of the intrusion increases the anion vacancy concentration.•Leads to flux of oxygen vacancies along intrusion, increasing the growth rate.