Resistively heated diamond-anvil cells have been used together with synchrotron x-ray diffraction to investigate the phase diagram of calcium up to 50 GPa and 800 K. The phase boundaries between the Ca-I (fcc), Ca-II (bcc), and Ca-III (simple cubic, sc) phases have been determined at these pressure-temperature conditions, and the ambient temperature equation of state has been generated. The equation of state parameters at ambient temperature have been determined from the experimental compression curve of the observed phases by using third-order Birch-Murnaghan and Vinet equations. A thermal equation of state was also determined for Ca-I and Ca-II by combining the room-temperature Birch-Murnaghan equation of state with a Berman-type thermal expansion model.

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A single streak camera line imaging velocimeter has been applied to Armco® iron plate impact experiments to study material response at the grain scale. The grain size and phase distribution were determined with electron back scatter diffraction. The optical system resolution and fringe size were optimised to suit the grain size distribution. Comparisons of the performance and merits of several analysis algorithms including the ‘Fourier transform’, ‘fringe tracking’, ‘quadrature’ and the ‘continuous wavelet transform’ have been made by application to synthetic data. Point heterodyne velocimetry measurements made at the same location on the target surface have been compared with the line imaging velocimetry data for confirmation.

Abstract. Under shock loading conditions, mild steel undergoes a solid-solid phase transition at approximately 13GPa. In this work 080M40 plain carbon steel bright round rolled bar, was machined and heat-treated to produce an annealed or a martensitic structure. These samples were shock loaded, by plate impact, and the material response recorded using in-situ manganin stress gauges and heterodyne velocimetry. The Hugoniot stress and material characteristics both above and below the phase transition pressure have been recorded.

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