The metallic glass Zr65Al7.5Cu27.5 exhibits a wide temperature range in the undercooled liquid region. This offers the possibility of examining the phenomena that occur during glass transition. We investigated this glass by x-ray diffraction and x-ray absorption spectroscopy (XAS) at room temperature and at elevated temperatures below and above the glass transition temperature. The total number of nearest neighbors determined by x-ray diffraction remained unchanged. Using XAS irreversible changes in the short range order (SRO) towards the SRO of crystalline Zr2Cu is observed in the nearest neighbor shell which is consistent with the x-ray diffraction results. The long range order was not affected by these changes. From the temperature dependence of the atomic mean-square relative displacements σ2, Debye temperatures were determined and they compare well with low temperature specific heat measurements. Above Tg the slope of σ2 increases drastically and is attributed to anharmonic effects.
We report the method and first examples of thermal expansion measurements of liquid metallic samples measured under μg conditions. The experiments were performed in an electromagnetic levitation facility (TEMPUS facility) on board the space orbiter Columbia (mission MSL-1). The sample was imaged by a high-resolution CCD camera with on-board recording. After the mission the video tapes were analyzed by digital image processing. First measurements were made with a molten Pd78Cu6Si16 sample in the temperature range of about 800 to 1150 °C. The measured value of the coefficient of volume expansion is 8.9×10−5/°C in this temperature range.
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