Investigation of the elementary mechanisms controlling dislocation/twin boundary interactions in fcc metals and alloys: from conventional to advanced TEM characterization
نویسندگان
چکیده
The elementary mechanisms controlling the interactions between lattice gliding dislocations and twin boundaries were carefully analyzed using conventional and advanced transmission electron microscopy techniques in both bulk coarsegrained Fe-Mn-C TWIP steels with deformation twins and nanocrystalline Palladium thin films with nanoscale growth twins. The results reveal that the individual dislocation/TB reactions depend mainly on the stacking fault energy of the material as well as the nature of the incoming dislocations nucleated during the plastic deformation of the material. It is also demonstrated that such investigation requires dedicated and specific microscopic techniques depending on the microstructure and the intrinsic properties of the crystallographic defects of the materials.
منابع مشابه
Dislocation–twin interactions in nanocrystalline fcc metals
Dislocation interaction with and accumulation at twin boundaries have been reported to significantly improve the strength and ductility of nanostructured face-centered cubic (fcc) metals and alloys. Here we systematically describe plausible dislocation interactions at twin boundaries. Depending on the characteristics of the dislocations and the driving stress, possible dislocation reactions at ...
متن کاملThe interaction mechanisms of a screw dislocation with a defective coherent twin boundary in copper
∑ 3{111} coherent twin boundary (CTB) in face-centered-cubic (FCC) metals and alloys have been regarded as an efficient way to simultaneously increase strength and ductility at the nanoscale. Extensive study of dislocation-CTB interaction has been carried out by a combination of computer simulations, experiments and continuum theory. Most of them, however, are based on the perfect CTB assumptio...
متن کاملHigh strain rate properties of metals and alloys
The high strain rate dependence of the flow stress of metals and alloys is described from a dislocation mechanics viewpoint over a range beginning from conventional tension/compression testing through split Hopkinson pressure bar (SHPB) measurements to Charpy pendulum and Taylor solid cylinder impact tests and shock loading or isentropic compression experiment (ICE) results. Single crystal and ...
متن کاملTwin intersection mechanisms in nanocrystalline fcc metals
Deformation twins have been reported to produce high strength and ductility. Intersections of deformation twins may affect the microstructural evolution during plastic deformation and consequently influence mechanical properties. However, the mechanisms governing twin-intersection behavior remain poorly understood. In this study, we investigated twin intersection mechanisms by observing twin tr...
متن کاملDislocation mechanisms and 3D twin architectures generate exceptional strength-ductility-toughness combination in CrCoNi medium-entropy alloy
Combinations of high strength and ductility are hard to attain in metals. Exceptions include materials exhibiting twinning-induced plasticity. To understand how the strength-ductility trade-off can be defeated, we apply in situ, and aberration-corrected scanning, transmission electron microscopy to examine deformation mechanisms in the medium-entropy alloy CrCoNi that exhibits one of the highes...
متن کامل