The effect of interstitial sinks on creep of a dispersion strengthened columbium-base alloy

The effects of interstitial sinks on the structure and creep behavior of the dispersion-strengthened columbium base alloy., D43 were examined. Interstitial sinks change the structure of the alloy and render it less creep resistant by reducing the carbon concentration and, therefore, the volume fraction of the dispersed phase. Where the interparticle spacing is small (<≈1 μ) the alloy is strengthened by the direct interaction of dislocations with particles. Where the interparticle spacing is large, subgrains are probably a more important structural feature strengthening the alloy. The creep rate can be described by the empirical expression (dot varepsilon = Asigma ^n e^{ - H/RT} ) , whereH (106 to 112 kcal per mole) andn (7.7 to 8.3) are independent of the amount of dispersed phase, andA is proportional to the reciprocal carbon concentrations in the range 100 to 800 ppm.