An analysis of specimen geometry effect on the creep life of inconel alloy X-750

Abstract

The effects of section size and specimen geometry (flat, tubular and solid specimens) on the creep behaviour of a nickel-base superalloy (Inconel X-750) have been elicited. The effect of the section size was observed in all three specimen geometries; time to fracture was progressively shortened as the specimen thickness was reduced. The creep behaviour exhibited by the alloy in the three specimen geometries was compared on the basis of similar section size. It emerged that the times to rupture of tubular specimens were considerably longer than those of flat and solid specimens while the minimum creep rate at all the applied stresses was found to be nearly unaffected by the specimen geometry. It is shown that the principle of the volume to surface ratio is applicable and the equivalence of creep life data in different geometries is obtained when a comparison is made using the ratio of the cross-sectional area to the perimeter as the normalizing parameter.