Positron annihilation study on deformation of high purity iron under different strain rate

Contributions from Different crystal defects to the positron annihilation S-parameter (the line-shape parameter of the Doppler broadening) are differentiated. It is concluded that, under slow strain rate, the S-- xi curve in high-purity Fe does not tend to saturation; the slower the strain rate, the more evident the "non-saturation phenomenon". As high-purity Fe is deformed, the increment in the S-parameter depends not only on dislocation density but also on vacancy concentration, and this is attributed to the so-called "non-saturation phenomenon" of the S-- xi curve to the strain-induced vacancies and their clusters.