Browsing by Author "Chladil, HF"

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    Evolution of composition and grain correlations upon phase transitions and micro-structural rearrangement processes followed in-situ by high energy x-ray diffraction
    (Materials Australia, 2007-07-03) Liss, KD; Yeoh, LA; Clemens, H; Chladil, HF; Bartels, A; Stark, A; Buslaps, T
    Two-dimensional powder diffraction using high-energy synchrotron x-rays is a powerful tool for bulk studies of materials and a short introduction of its advantages is given here.
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    In and ex situ investigations of the β-phase in a Nb and Mo containing gamma-TiAl based alloy.
    (Elsevier, 2008-06) Clemens, H; Chladil, HF; Wallgram, W; Zickler, GA; Gerling, R; Liss, KD; Kremmer, S; Guther, V; Smarsly, W
    In β-stabilized Ti-43Al-4Nb-1Mo-0.1B alloy (composition in atomic percent) the correlation between the occurrence of β-phase and temperature was analyzed experimentally and compared to thermodynamic calculations. Results from in situ high-energy X-ray diffraction, texture measurements, heat treatments, scanning electron microscopy, and temperature-dependent flow stress measurements were used to study the evolution of the β-phase with temperature. Thermodynamic calculations based on the CALPHAD method were applied to correlate the phases developed in the β-solidifying TiAl based alloy under investigation. This alloy is characterized by an adjustable β-phase volume fraction at temperatures where hot-work processes such as forging and rolling are conducted. Due to a high volume fraction of β-phase at elevated temperatures the hot-extruded alloy can be forged under near conventional conditions. © 2008, Elsevier Ltd.
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    In situ high-energy X-ray diffraction study and quantitative phase analysis in the α+γ phase field of titanium aluminides
    (Elsevier, 2007-12) Yeoh, LA; Liss, KD; Bartels, A; Chladil, HF; Avdeev, M; Clemens, H; Gerling, R; Buslaps, T
    Quantitative atomic structure and phase analysis in the titanium aluminide intermetallic system of composition Ti–45Al–7.5Nb–0.5C (at.%) was conducted in situ by use of high-energy X-ray diffraction from a synchrotron and evaluated using the Rietveld method, implementing a model for atomic order in the α-phase which describes the order to disorder transition α2→α at the eutectoid temperature. The order parameter exhibits unexpected behavior and is entangled with the competition of different kinetic processes. © 2007, Elsevier Ltd.