An investigation was made of the strain-rate dependence of the brittle-to-ductile transition temperature in pre-cracked W single crystals and polycrystals. It was found that there was an unambiguous Arrhenius relationship over 4 decades of strain rate giving an activation energy, for the process controlling the brittle-to-ductile transition, of 1.05eV. This was equal to the activation energy for double-kink formation on screw dislocations, thus suggesting that their motion controlled the brittle-ductile transition.

Strain-Rate Dependence of the Brittle-to-Ductile Transition Temperature in Tungsten. A.Giannattasio, S.G.Roberts: Philosophical Magazine, 2007, 87[17], 2589-98