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Abstract: Using cold graphite mold casting method, Al-based chill-zone alloys cylinders of millimeter scale thickness [Y. Li, K. Georgarakis, S.J. Pang, A. LeMoulec, T. Zhang, A.R. Yavari, unpublished research.] were prepared. Using high-resolution scanning electron microscopy (HRSEM), it was found that hard submicron crystalline surface layers of thickness about 200μm form when the melt can be undercooled. The structure and the thermal properties of the chill-zone alloy were examined by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). A metastable phase Al19Ni5Y3 nucleated during cooling then transformed to equilibrium intermetallics after annealing. The chill-zone alloy shows high mechanical strength in excess of 1GPa at high ambient temperatures and good plasticity. The combination of high strength and good plasticity will be discussed in relation to the special structure of the chill-zone alloy. [Copyright &y& Elsevier]

Abstract The influence of global interactions between the static atomic structure and the valence electrons on structure formation in binary Al-(Ni,Cu,Zr), Zr-(Ni,Cu) and ternary Al-(Ni,Cu)-Zr metallic glasses is investigated over wide concentration ranges and discussed in terms of a Hume-Rothery-like theory by analysing and comparing data available in the literature. The results suggest that global interactions lead to an improvement of thermal stability and glass-forming ability. A complete understanding of structure formation in the considered alloys is assumed to be possible only by taking into account both local and global effects. • The effect of global interactions on thermal stability and glass-forming ability in Al-(Ni,Cu)-Zr metallic glasses is analysed. • A Hume-Rothery-like effect according to a mean valence of 1.5 electrons per atom plays a major role. • Local and global effects mutually support each other to yield the energetically most favorable structure. • Correlations with other properties are pointed out. [ABSTRACT FROM AUTHOR]

The present report is dedicated to the first observation of pseudoelastic behaviour of the non-stoichiometric intermetallic compound Ti 75.5 Sn 24.5 . Strain recovery of the material was observed using a compressive cyclic loading–unloading test and microhardness indentation at room temperature. The stress–strain curve during loading–unloading processes forms pseudoelastic loop with correspondent apparent Young’s modulus about 30 GPa while irregular shape of microhardness imprints indicates graphically material’s recovery. Microstructure of the material and its changes during deformation were observed using metallographic techniques. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new orthorhombic phase of the intermetallic compound Ti3Sn was found. [•] A reversible orthorhombic-to-hexagonal transition into Ti3Sn was observed using XRD. [•] The unit cell and space group of orthorhombic phase are defined. [•] Crystallographic relations between orthorhombic and hexagonal phases are analyzed. [ABSTRACT FROM AUTHOR]