Evaluation of the Parameters of a Constitutive Mode1 for b.c.c. Metals Based on Thermal Activation F. Buy, J. Farre, J.R. Klepaczko et G. Talabart J. Phys. IV France, 07 C3 (1997) C3-631-C3-636 DOI: 10.1051/jp4:19973108