Relative mobility of screw versus edge dislocations controls the ductile-to-brittle transition in metals.

ABSTRACT: Body-centered cubic metals including steels and refractory metals suffer from an abrupt ductile-to-brittle transition (DBT) at a critical temperature, hampering their performance and applications. Temperature-dependent dislocation mobility and dislocation nucleation have been proposed as the potential factors responsible for the DBT. However, the origin of this sudden switch from toughness to brittleness still remains a mystery. Here, we discover that the ratio of screw dislocation velocity to edge dislocation velocity is a controlling factor responsible for the DBT. A physical model was conceived to correlate the efficiency of Frank-Read dislocation source with the relative mobility of screw versus edge dislocations. A sufficiently high relative mobility is a prerequisite for the coordina

SUBMITTER: Lu Y 

PROVIDER: S-EPMC8449375 | biostudies-literature | 2021 Sep

REPOSITORIES: biostudies-literature