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Mechanical properties of lithium molybdate single crystals, Li2MoO4, are studied from room temperature to 650 °C. Density functional theory calculations gave the seven elastic constants of the rhombohedral crystal at 0 K. Brillouin light scattering experiments delivered comparable values at room temperature, and measurements up to 650 °C show a linear decrease in the constants with temperature. Nano-indentation results were typical of a brittle material with a low Young modulus and allowed deriving Young's moduli, for c (63 GPa) and m (48 GPa) faces, in agreement with those computed from measured elastic constants. Compressive rupture tests were performed. At 650 °C, the rupture stress was in the range 2–7.5 MPa. No clear evidence of a plastic regime was observed before cracking, even at temperatures close to the melting point. [ABSTRACT FROM AUTHOR]

Abstract: LHPG and zone melting solidification of Al2O3‐YAG‐ZrO2:Y eutectic samples is performed in order to investigate intrinsic and extrinsic electric field phenomena. An intrinsic electric field is measured during solidification. Its decay with distance from the interface, and its relaxation with time, show that it is induced by the accumulation of positive electric charges at the solid‐liquid interface, that diffuse away when pulling is stopped. Under extrinsic electric field, a significant modification of the eutectic phase diagram is observed. The charged diffusive boundary layer interacts with the field and the microstructure is impacted. Those observations suggest that the segregating species is zirconium ions. [ABSTRACT FROM AUTHOR]

The most efficient method to investigate nucleation phenomena is to measure the undercooling temperature at the beginning of the solidification process since it gives information about whether or not a certain substrate favors the heterogeneous nucleation. In this work a suitable experimental setup has been designed and developed for the study of nucleation phenomena, where a silicon droplet is directly placed and melted on a substrate. The melting-solidification process was filmed and the undercooling temperature was simultaneously measured by monochromatic and bichromatic pyrometers. For all the studied substrates the melting process started from the bottom of the sample where there was a contact with the substrate. In the case of zyarock and fused silica substrates, on which we focalize in the present paper, the temperature profile of the silicon sample presented a temperature plateau during melting and a typical cooling curve showing undercooling, recalescence and a plateau denoting that solidification occurred under isothermal conditions. It was also found that the nature of the substrates influences the measured undercooling values and the shape of the solidified silicon droplets. [ABSTRACT FROM AUTHOR]

Abstract: LHPG and zone melting solidification of Al2O3‐YAG‐ZrO2:Y eutectic samples is performed in order to investigate intrinsic and extrinsic electric field phenomena. An intrinsic electric field is measured during solidification. Its decay with distance from the interface, and its relaxation with time, show that it is induced by the accumulation of positive electric charges at the solid‐liquid interface, that diffuse away when pulling is stopped. Under extrinsic electric field, a significant modification of the eutectic phase diagram is observed. The charged diffusive boundary layer interacts with the field and the microstructure is impacted. Those observations suggest that the segregating species is zirconium ions. [ABSTRACT FROM AUTHOR]