Extensive atomistic simulations based on the quasiparticle (QA) approach are performed to determine the momentous aspects of the displacive fcc/bcc phase transformation in a binary system. We demonstrate that the QA is able to predict the major structural characteristics of fcc/bcc phase transformations, including the growth of a bcc nuclei in a fcc matrix, and eventually the formation of an internally twinned structure consisting in two variants with Kurdjumov-Sachs orientation relationship. At atomic level, we determine the defect structure of twinning boundaries and fcc/bcc interfaces, and identify the main mechanism for their propagation. In details, it is shown that twin boundaries are propagated by the propagation of screw dislocations in fcc along the <-1-11>_α direction, while the propagation of fcc screw dislocations along coherent terrace edges is the pivotal vector of the fcc/bcc transformation. The simulation results are compared with our TEM and HRTEM observations of Fe-rich bcc twinned particle embedded in the fcc Cu-rich matrix in the Cu-Fe-Co system.
Transformation-mediated twinning governs plasticity in body-centered cubic nanocrystals under extreme loading
University of West Bohemia in Pilsen(西波希米亚大学);University of Helsinki(赫尔辛基大学);National Centre for Nuclear Research(国家核研究中心);Universitat Politècnica de Catalunya(加泰罗尼亚理工大学)
Effect of cold rolling strain on the microstructural evolution in equimolar MoNbTaTiZr refractory complex concentrated alloy: Comprehensive characterization
FZU – Institute of Physics of the Czech Academy of Sciences(捷克科学院物理研究所);Department of Materials Science and Engineering, Graduate School of Science and Technology, Kumamoto University(熊本大学理工学院材料科学与工程系);Department of Materials, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague(捷克布拉格理工大学核科学与物理工程学院材料系)
Multiscale modeling of plastic deformation of molybdenum and tungsten: I. Atomistic studies of the core structure and glide of 1/2<111> screw dislocations at 0 K