First-principles calculations of proton defect properties in Ca-doped YPO.

YPO has a xenotime-type structure with one-dimensional percolating channels along the -axis, and Ca-doped YPO exhibits proton conduction. In the present study, using first-principles calculations, we investigate the behaviors of proton solutions in 3 mol% Ca-doped YPO in the intermediate temperature range on the basis of point-defect formation energies, defect concentrations, and migration barriers. Although the charge-neutrality condition is mainly satisfied by and defects within the defect formation energy diagrams, the defect complex has the lowest formation energy and the highest concentration among examined defects under various temperature and partial-pressure conditions.

Dislocation Structure in Hot Deformed Al-Zn-Mg Alloy by X-ray Line Profile Analysis.

The microstructure of extruded Cu-free Al-Zn-Mg alloy is studied. Hot torsion tests are performed on a Cu-free Al-Zn-Mg alloy to investigate the effect of large strain deformation on the dislocation behavior. The dislocation structure is characterized by X-ray diffraction profile analysis, and the effective stress-strain curves are obtained by hot torsion tests.

High Temperature Deformation Characteristics of Al-Zn-Mg Alloy Modified with CaO-Added Mg.

Hot torsion tests were performed on an Al-Zn-Mg alloy modified with CaO-added Mg to investigate the effects of the Mg additive on the high temperature deformation characteristics. Effective stress- strain curves and processing maps were established from the experimental results under a range of deformation conditions. The fracture strain of the CaO-added Al-Zn-Mg alloy was higher than that of the Al-Zn-Mg alloy.