Creep deformation of iron strengthened by MX type particles

Creep deformation of bcc iron strengthened by TaN or TaC (hereinafter MX) at about 650 °C has been studied. Nano-scaled MX particles significantly lower minimum creep rate of bcc iron and retard the onset of macroscopic accelerating creep. Shrinkage during creep was observed in Ta and C containing steel. Rupture data indicate that the addition of 0.1% Ta with sufficient N is adequate for high creep resistance. However, TaC particles are stable even under applied stress as compared with TaN. In comparison, TaN particles easily grow under stress, so that TaC containing steels may provide engineering improvements under low stress.