Deformation twinning evolution from a single crystal in a face-centered-cubic ternary alloy

Abstract

Deformation twinning evolution from a single crystal is conducted by molecular dynamics simulations, to elucidate a twinned face-centered-cubic alloy in an experiment with hardness up to 100 times as that of single crystals, and with ductility simultaneously. Critical twinning stress of cadmium zinc telluride (CdZnTe or CZT) calculated is 1.38 GPa. All the twin boundaries are along the (11-1) orientation, except the one with the (-111) plane that supports the indentation, interpreting the unidirectional and boundary-free characteristics, confirmed in the experiment. Three twin thicknesses after unloading are 3.2, 3.5, and 16 nm, which is consistent with the experimentally repeated pattern of a lamellar twin with thickness larger than 12.7 nm, followed by one or several twins with thicknesses smaller than 12.7 nm. An inverse triangle of a twin combining with three twins generate a synergistic strengthening effect through the hardening and softening functions, illuminating the ultrahigh hardness demonstrated in the experiment. Twinning takes place in loading, and detwinning occurs in unloading, which expounds the high ductility observed in the experiment.

Investigation of Interaction between Dislocation Loop and Coherent Twin Boundary in BCC Ta Film during Nanoindentation

“…For example, Fu et al [ 33 ] relaxed the nanotwinned vanadium nitride at T = 300 K for 30 ps. As the time step for MD simulations is of fs, high indentation speed of 10–100 m/s is commonly used to perform MD nanoindentation simulations [ 35 , 36 , 37 , 38 , 39 ]. For example, Zhang et al [ 38 ] perform MD nanoindentation with the speed of 100 m/s.…”

“…As the time step for MD simulations is of fs, high indentation speed of 10–100 m/s is commonly used to perform MD nanoindentation simulations [ 35 , 36 , 37 , 38 , 39 ]. For example, Zhang et al [ 38 ] perform MD nanoindentation with the speed of 100 m/s. Gao et al [ 39 ] studied the influence of the indentation speed on the results in their simulations of nanoindentation on Fe using the indentation speed spanning from 10 to 100 m/s, and found no significant influence on the main results.…”

Deformation Twinning and Detwinning in Face‐Centered Cubic Metallic Materials

“…[37,82,83] Deformation twinning has been considered to be an effective way to increase both strength and ductility. [37,38,[84][85][86] It is generally believed that TBs have a similar effect as GBs, which are strong barriers for dislocation motion due to the Hall-Petch effect. Twins in Cu, Ni, and steel with TB spacing of tens to hundred nanometers show an obvious Hall-Petch-type strengthening effect.…”

A novel approach of chemical mechanical polishing for cadmium zinc telluride wafers

“…Furthermore, CZT is widely used in medical imaging, homeland security, and spaceborne X-ray and gamma-ray astronomy145. This is attributed to its high gamma-ray absorption coefficient and high electrical resistivity, derived from the high atomic number and wide bandgap, respectively1.…”

“…Cadmium zinc telluride (CdZnTe or CZT) is a representative for the third-generation soft-brittle semiconductors in room temperature radiation detection, as well as a substrate for epitaxial growth of lattice-matched mercury cadmium telluride (HgCdTe or MCT) films used for infrared detectors 1 2 3 . Furthermore, CZT is widely used in medical imaging, homeland security, and spaceborne X-ray and gamma-ray astronomy 1 4 5 . This is attributed to its high gamma-ray absorption coefficient and high electrical resistivity, derived from the high atomic number and wide bandgap, respectively 1 .…”