Young’s Modulus of Single Crystals of Palladium at High Temperatures

Abstract

Single crystals of palladium having a long length were prepared and their thermal expansions and Young’s moduli were measured over the temperature range 0° to 600°C by a dilatometer and by means of a vibrator-controlled oscillator system. From the measured values, the Young’s moduli in three principal orientations of the single crystals were calculated. The results show that the Young’s moduli at 20°C are 7.35, 13.77 and 19.44×10⁵ kg/cm² in the orientations of ⟨100⟩, ⟨110⟩ and ⟨111⟩ of the single crystal, respectively. The Young’s moduli in the ⟨100⟩ and ⟨110⟩ orientations of the single crystals decrease with increasing temperature, while the modulus in the ⟨111⟩ orientation increases to a maximum at about 250°C and then gradually decreases. The calculated value of the Young’s modulus for a polycrystal agrees fairly well with the measured value in the polycrystal specimen prepared by melting.