P. V. Mohan Rao

The high-temperature thermal expansion of Ni3Al measured by X-ray diffraction and dilation methods

The lattice parameters of Ni3Al have been determined accurately for the temperature range 25 to 594 degrees C by a high-temperature X-ray powder diffraction method. These data are used to evaluate the coefficients of thermal expansion at various temperatures. The thermal expansion of Ni3Al has also been measured from 25 to 1000 degrees C by a dilation method. The thermal expansion values obtained by the dilation method are in good agreement with those determined by the X-ray diffraction method at around room temperature, but the agreement deteriorates with increase in temperature.

High temperature thermal expansion characteristics of Ni3Al alloys

The thermal expansion of Ni3Al alloys with and without ternary additions have been investigated with the aid of a dilatometer. The Ni3Al alloys were studied over the temperature range 25–1000 °C. The coefficient of thermal expansion α of all the aluminides studied in this investigation varies linearly with the temperature. The coefficient of thermal expansion of Ni3Al is found to show an increase with the decrease in Al content from stoichiometric composition. B and Zr additions decrease the value α of Ni3Al alloys at room temperature while Hf and Ti additions do not alter it significantly.

Thermal expansion of V3Ga

The thermal expansion of V3Ga has been studied using the X-ray method in the temperature range 299-691 K. The thermal expansion coefficient increases linearly with temperature over the range studied, within experimental error. The room-temperature value of alpha is compared with that obtained from specific heat data. The Gruneisen constant ( gamma G) for vanadium-based A15 compounds is found to be 1.61.

X-ray studies on thermal expansion of CrSbO4

Variation non lineaire des parametres cristallins a et c de CrSbO 4 avec la temperature. Variation du coefficient de dilatation thermique perpendiculaire proportionnelle a la temperature. Variation du coefficient parallele inversement proportionnelle a la temperature

Effect of third elements on the microhardness of Ni3Al

Abstract The room-temperature microhardness of Ni 3 Al with and without third elements has been studied using the Vickers indentation technique. In pure Ni 3 Al phase alloys, the hardness value increased with decreasing Al concentration from stoichiometric composition. This increase is attributed to the defects present at off-stoichiometric compositions. The addition of third elements Hf, Zr, Ti and Si increased the hardness value of Ni 3 Al suggesting the solid-solution strengthening effect. The presence of 0.20 at% boron in Hf- and Zr-containing alloys shows a softening effect at small concentrations of Hf and Zr.

High temperature lattice thermal expansion of ErRh3B

Determination par diffraction de rayons X des parametres cristallins entre 308 et 624 K. Evaluation a partir de ces donnees du coefficient de dilatation thermique

Lattice thermal expansion of V3As

Mesure des parametres cristallins entre 26 et 479 K, et de la valeur du coefficient de dilatation thermique