Effect of Nitrogen in Solution on High Temperature Creep Resistance of High Purity Chromium

Abstract

The effect of solute nitrogen on the high temperature creep resistance of pure chromium has been investigated in argon atmosphere using the specimens aged for 3.6 × 10⁵s at 1273K (200ppm Nitrogen) and as solution treated (without nitrogen). The minimum creep rate of the prior-aged specimen was lower than that of the as solution treated one. The evolution of subgrains during creep was suppressed in the prior-aged specimen compared with the as solution treated one. Stress reduction tests were conducted at the minimum creep rate, in order to evaluate the creep rates under the same subgrain size. Under the same subgrain size, the creep rate of the prior-aged specimen was 1/5 of the as solution treated one. The higher creep resistance of the prior-aged specimen was attributed to the solid solution strengthening due to nitrogen.