Abstract
Rod-form single crystals of Pd-50%Au alloy about 2 mm in diameter and 7∼10 cm in length were prepared and the thermal expansion and Young’s modulus were measured over the temperature range −150° to 600°C with a dilatometer and by means of a vibrator-controlled oscillator system, respectively. From the measured values, Young’s moduli in the three principal directions of the single crystals were calculated. From the results it has been known that the Young’s moduli at 20°C are 5.76×105 kg/cm2, 11.80×105 kg/cm2 and 18.10×105 kg/cm2 in the ⟨100⟩, ⟨110⟩ and ⟨111⟩ directions of the single crystals, respectively. The Young’s modulus in the ⟨100⟩ direction of the single crystals increases with increasing temperature, attains a maximum at about 400°C and then gradually decreases, while the Young’s moduli in the ⟨110⟩ and ⟨111⟩ directions monotonously decrease. The calculated value for Young’s modulus of a polycrystal was found to agree fairly well with the measured one in the polycrystal specimen prepared by melting.
