Fracture Energy Measurement of Prismatic Plane and Σ2 Boundary in Cemented Carbide

The grain boundary network of WC in WC-Co is important, as cracks often travel intergranularly. This motivates the present work, where we experimentally measure the fracture energy of Σ2 twist grain boundaries between WC crystals using a double cantilever beam opened with a wedge under displacement control in a WC-10wt%Co sample. The fracture energy of this boundary type was compared with cleaving {$$10\overline{1}0$$ 10 1 ¯ 0 } prismatic planes in a WC single crystal. Fracture energies of 7.04 ± 0.36 Jm−2 and 3.57 ± 0.28 Jm−2 were measured for {$$10\overline{1}0$$ 10 1 ¯ 0 } plane and Σ2 twist boundaries, respectively.

Review and Detail Classification of Stacking Faults in 4H-SiC Epitaxial Layer by Mirror Projection Electron Microscopy

Stacking faults (SFs) in 4H-SiC epitaxial wafers were inspected by using a mirror projection electron microscope (MPJ) [1, 2]. Dark and bright line contrasts of SFs in MPJ images represent surface morphology and crystal defects located in the epitaxial layer. Inspected SFs were classified into three types of SFs on the basis of the MPJ images. After classification, a cross section of each type of SF was observed by transmission electron microscopy (TEM) to verify the classification result. Complex SFs classified by MPJ images consisted of prismatic plane and basal plane SFs.

H effect on the plasticity of Ti575 alloy

Adsorption of hydrogen (H) can result in severe performance degradation of Ti alloys. In this study, the effect of H on the plasticity of Ti-5Al-7 5V-0.5Si (Ti575) alloy is investigated. High resolution digital image correlation (HRDIC) is employed to elucidate the effect of H on the strain distribution and dislocation slip character of the alloy during mechanical loading. It is found that H enhances slip heterogeneity and promotes the formation of long and sparse prismatic slip bands in the α phase, which can extend to across several grains. Such heterogenous prismatic slip bands are likely to originate from the lenticular hydrides, which have the prismatic plane as their habit plane. In addition, H also shows considerable effect on the plasticity of β phase, which facilitates the slip transmission and enhances the slip localisation.

Conversion of Basal Plane Dislocations to Threading Edge Dislocations by Annealing 4H-SiC Epilayers at High Temperatures

Basal plane dislocations (BPDs) converting to threading edge dislocations (TEDs) has been observed in 4H-SiC epilayers after thermal annealing at high temperatures. Grazing incidence reflection synchrotron X-ray topography was used to investigate the dislocation behaviors. It is argued that the conversion is achieved by constricted BPD segments cross-slipping to the prismatic plane and TED glide on its slip plane. Higher conversion ratio and better surface morphology were achieved by performing ion implantation and annealing before epitaxial growth.

Anisotropy of Mechanical Properties and Microstructure Evolutions of Tensile AZ80 Magnesiumat Room Temperature

It is obviously different mechanical properties of the rolled magnesium alloy plate when stretched along different directions at room temperature. In this study, three groups of samples for uniaxial tension were cut from the as-rolled AZ80 plate with their tension directions either at 0°, 45°or 90°to the rolled direction (RD) of the sheet. Results show that the ductility of the 45°samples was significantly better than that of 0°and 90°samples. The electron backscatter diffraction (EBSD) technique was used to investigate the microstructure and textures evolution. Along with the increase of deformation, more low-angle grain boundaries arise in the 0°and 45°samples than the 90°samples. At the same time, the texture components that {10-10} prismatic plane perpendicular to the tension direction were significantly enhanced in three groups of samples.

First-Principles Study on the Ideal Strengths of Typical Hcp Metals

The ideal strengths of several hcp metals (Be, Mg, Ti, Zn, Y, Zr and Ru) have been investigated by first-principles stress–strain calculations. The results reveal that the ideal shear strengths of these hcp metals occur mainly on basal plane or prismatic plane. Particularly, for basal plane the peak shear stress in direction is smaller than that in direction. The calculated tensile strengths and elongations in direction are broadly consistent with the available theoretical results. Furthermore, both the ideal shear and tension strengths become stronger with the decreasing of c/a for these simple metals or transition metals. The calculated electronic structure further reveals the inherent mechanism of hcp metals.