Twinning is a fundamental deformation mode that competes against dislocation slip in crystalline solids. In metallic nanostructures, plastic deformation requires higher stresses than those needed in their bulk counterparts, resulting in the 'smaller is stronger' phenomenon. Such high stresses are thought to favour twinning over dislocation slip. Deformation twinning has been well documented in ...

Deformation twinning, which is a type of plastic deformation, has been particularly investigated in metal materials. However, only a few examples are found in organic solids. We observed mechanical twinning deformation on a simple ferrocene crystal, which is considered the most representative organometallic compound, and evaluated the crystal structures under the twinning state and the shear de...

In recent years, TRIP/TWIP steels have been the focus of great attention thanks due to their excellent tensile strength-ductility combination. The compression tests were performed at different temperatures from 25 to1000°C to study the mechanical behavior of advanced austenitic steel with 21% manganese plus bearing Ti. The results indicated that the plastic deformation is controlled by deformat...

This article systematically overviews the grain size effect on deformation twinning and detwinning in face-centered cubic (fcc) metals. With decreasing grain size, coarse-grained fcc metals become more difficult to deform by twinning, whereas nanocrystalline (nc) fcc metals first become easier to deform by twinning and then become more difficult, exhibiting an optimum grain size for twinning. T...

We draw upon existing knowledge of twinning and slip mechanics to develop a diffraction analysis model that allows for empirical quantification of individual deformation mechanisms to the macroscopic behaviors of low symmetry and phase transforming crystalline solids. These methods are applied in studying elasticity, accommodation twinning, deformation twinning, and slip through neutron diffrac...

Nanocrystalline (nc) materials can be defined as solids with grain sizes in the range of 1–100 nm. Contrary to coarse-grained metals, which become more difficult to twin with decreasing grain size, nanocrystalline face-centered-cubic (fcc) metals become easier to twin with decreasing grain size, reaching a maximum twinning probability, and then become more difficult to twin when the grain size ...

Macroscopic strain was hitherto considered a necessary corollary of deformation twinning in coarse-grained metals. Recently, twinning has been found to be a preeminent deformation mechanism in nanocrystalline face-centered-cubic (fcc) metals with medium-to-high stacking fault energies. Here we report a surprising discovery that the vast majority of deformation twins in nanocrystalline Al, Ni, a...

As expected from the alloy design procedure, combined Twinning Induced Plasticity (TWIP) and Transformation Induced Plasticity (TRIP) effects are activated in a metastable β Ti-12(wt.%)Mo alloy. In-situ Synchrotron X-ray diffraction (XRD), electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) observations were carried out to investigate the deformation mechanisms an...

Twinning on the plane is a common mode of plastic deformation for hexagonal-close-packed metals. Here we report, by monitoring the deformation of submicron-sized single-crystal magnesium compressed normal to its prismatic plane with transmission electron microscopy, the reorientation of the parent lattice to a 'twin' lattice, producing an orientational relationship akin to that of the conventio...

The plastic deformation behavior of twinning-induced plasticity steels of composition Fe–25Mn–3Si–3Al are investigated by means of in situ synchrotron high-energy X-ray diffraction and compared to self-consistent simulations. It is the first time the alternating interaction of {1 1 1} <1 1 0> slip and {1 1 1} <1 1 2> twinning have been directly observed in situ while undergoing uniaxial tension...