Effect of Interstitial Elements on Hall–Petch Coefficient of Ferritic Iron

抄録

Yield strength was investigated in iron with different grain size and different contents of carbon and nitrogen. The Hall–Petch coefficient; k_y is originally very small in high purity iron (about 100 MPa·μm^1/2) but it increases with increasing the amount of solute carbon content. The value of k_y is enlarged to around 550 MPa·μm^1/2 by 60 ppm of solute carbon and levels off at around 600 MPa·μm^1/2 in the region above 60 ppm solute carbon. On the other hand, nitrogen hardly influences the k_y value. The mechanism of the change in Hall–Petch coefficient was then discussed in terms of the grain boundary segregation of carbon and nitrogen atoms.