title: Onset mechanism of strain-rate-induced flow stress upturn.
abstract: The strain-rate response of flow stress in a plastically deforming crystal is formulated through a stress-sensitive dislocation mobility model that can be evaluated by atomistic simulation. For the flow stress of a model crystal of bcc Fe containing a 1/2[111] screw dislocation, this approach describes naturally a non-Arrhenius upturn at high strain rate, an experimentally established transitional behavior for which the underlying mechanism has not been clarified. Implications of our findings regarding the previous explanations of strain-rate effects on flow stress are discussed.
authors.affiliation: Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Yue
authors.initials: Y
authors.lastname: Fan
authors.forename: Yuri N
authors.initials: YN
authors.lastname: Osetsky
authors.forename: Sidney
authors.initials: S
authors.lastname: Yip
authors.forename: Bilge
authors.initials: B
authors.lastname: Yildiz