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The ultra-precision diamond cutting process exhibits strong size effects due to the ultra-small depth of cut that is comparable with the cutting edge radius. In the present work, we elucidate the underlying machining mechanisms of single crystal cerium under diamond cutting by means of molecular dynamics simulations, with an emphasis on the evaluation of the effect of depth of cut on the cutting process by using different depths of cut. Diamond cutting experiments of cerium with different depths of cut are also conducted. In particular for the smallest depth of cut of 0.2 nm, shallow cutting simulations varying the sharpness of the cutting edge demonstrate that an atomically sharp cutting edge leads to a smaller machining force and better machined surface quality than a blunt one. Simulation results indicate that dislocation slip is the dominant deformation mechanism of cerium under diamond cutting with each depth of cut. Furthermore, the analysis of the defect zone based on atomic radial distribution functions demonstrates that there are trivial phase transformations from γ-Ce to δ-Ce occurred in both the machined surface and the formed chip. It is found that there is a transition of material removal mode from plowing to cutting with the increase of the depth of cut, which is also consistent with the diamond cutting experiments of cerium with different depths of cut. [ABSTRACT FROM AUTHOR]

The microstructures and optical properties of 5% 6 Li: Ce 3 x Y 3(1-x) Al 5 O 12 (x = 0.001, 0.003, 0.05, 0.01, 0.02) transparent ceramics prepared by solid-state reaction and vacuum sintering were investigated in this paper. The results revealed that the grain size of 6 Li,Ce:YAG ceramics at this ration conditions is 4 μm–20 μm. With the doping of Ce 3+ , the transmittance of 6 Li,Ce:YAG ceramics decreases from 82% (x = 0.001) to 67% (x = 0.02) at 800 nm, and the intensity of transmittance peak at 340 nm and 460 nm increases. The emission peaks show red shift at around 530 nm with the increasing of Ce 3+ concentration. [ABSTRACT FROM AUTHOR]

Machined surface quality in terms of residual stress and surface roughness has an important influence on the performance of devices and components. In the present work, we elucidate the formation mechanisms of residual stress and surface roughness of single crystalline cerium under ultraprecision diamond cutting by means of molecular dynamics simulations. Influences of machining parameters, such as the rake angle of a cutting tool, depth of cut, and crystal orientation of the workpiece on the machined surface quality were also investigated. Simulation results revealed that dislocation activity and lattice distortion are the two parallel factors that govern the formation of both residual stress and surface roughness. It was found that both distributions of residual stress and surface roughness of machined surface are significantly affected by machining parameters. The optimum machining parameters for achieving high machined surface quality of cerium by diamond cutting are revealed. [ABSTRACT FROM AUTHOR]