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Abstract: Ceramics based on LnTiTaO6 (Ln =La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) were prepared using a conventional solid-state ceramic route. The structure and microstructure of the samples were analyzed using scanning electron microscopy, synchrotron X-ray powder diffraction and neutron diffraction techniques. The unit cell volume of the ceramics decreased with a decrease in ionic radius of the rare-earth ions until a phase change was seen at Ho where the space group changed from Pnma to Pbcn. The results confirmed that the boundary of the aeschynite to euxenite phase change that lies between DyTiTaO6 and HoTiTaO6 and demonstrate that this is a result of distortion of the channels in the aeschynite structure. [Copyright &y& Elsevier]

Abstract: This paper investigates the effect of both the mixing technique and heating rate during cure on the dispersion of montmorillonite (MMT) clay in an epoxy resin. The combination of sonication and using a 10°C/min heating rate during cure was found to facilitate the dispersion of nanoclay in epoxy resin. These processing conditions provided a synergistic effect, making it possible for polymer chains to penetrate in-between clay galleries and detach platelets from their agglomerates. As the degree of dispersion was enhanced, the flexural modulus and strength properties were found to decrease by 15% and 40%, respectively. This is thought to be due to individual platelets fracturing in the nanocomposite. Complementary techniques including X-ray diffraction (XRD), small angle X-ray scattering (SAXS), scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM–EDX), transmission electron microscopy (TEM) and optical microscopy were essential to fully characterise localised and spatial regions of the clay morphologies. [Copyright &y& Elsevier]

Abstract: The β-phase of Au7Cu5Al4 undergoes a reversible shape-memory phase transformation, however there has been some uncertainty regarding the crystal structure or structures of the parent phase. Here we show that, under equilibrium conditions, the parent phase possesses the L21 structure between its A p (about 79°C) and ∼630°C, and the B2 primitive cubic structure between ∼630°C and its melting point. It melts directly from B2 into the liquid state and hence never achieves the random bcc A2 structure that has been previously mooted. Splat-cast samples of the alloy are martensitic, proving that development of equilibrium order and defect concentration are not pre-requisites for the A → M transformation to occur. [Copyright &y& Elsevier]