Effect of phosphorus on the mechanical behavior of a Zr-Nb alloy

The flow stress of Zr-1.0Nb increased with the addition of 20 ppm phosphorous and the activation volume decreased with the addition of 300 ppm phosphorous at room temperature. The rate-controlling mechanism of the deformation of Zr-Nb-P is thought to be the dislocation-solute interaction in which the segregation of alloying elements affects the activation length. Less effective strengthening of phosphorous in Zr-Nb compared to sulphur was explained by a smaller electrostatic interaction between phosphorous atoms and dislocations.