Crystallization of glassy selenium during its plastic deformation

Crystallization of glassy selenium (Se) during its plastic deformation has been investigated in the temperature interval between 60 degrees C and 95 d egrees C. We found that plastic reshaping of small Se pellets into thin dis cs greatly enhances the notoriously sluggish transition from glassy to crys talline state. However, the content of the crystalline phase in the deforme d samples is found to be strongly dependent upon the temperature of the pro cess. While the 30-min long reshaping at 60 degrees C and 95 degrees C give s only partially crystallized samples (6% and 10%, respectively), an equall y long process at 80 degrees C gives 100% crystallized samples. Average cry stallite size in the samples prepared at 60 degrees C and 80 degrees C is v ery similar (25 nm and 15 nm, respectively), but in the sample prepared at 95 degrees C the grains are much larger: about 80 nm. The results are discu ssed taking into account the possibility that the mechanism of plastic defo rmation enhances both the nucleation frequency and the rate of crystal grow th. (C) 2000 Elsevier Science B.V. All rights reserved.