Abstract
The high temperature creep properties of a pure chromium have been investigated by comparing with that of a gamma single phase Ni-20Cr alloy. The larger creep resistance and creep rupture strength of the pure chromium rather than those of the Ni-20Cr alloy were attributed to the decrease in the ratio of testing temperature to the melting point due to the difference of the melting point between a chromium and a nickel.
The higher creep rupture ductility of the pure chromium than that of a Ni-20Cr resulted from the evolution of subgrain followed by dynamic recrystallization to inhibit the initiation and propagation of cracks. Above 50MPa, the increase in the stress exponent of minimum creep rate, n value, of the pure chromium with increase in the stress could be explained by the grain refining due to the evolution of subgrains followed by the dynamic recrystallization.
