Formation of macrosegregation structure in (Al 0.345 Bi 0.655 ) 90 Sn 10 (mass percent, the same below) immiscible alloy was investigated by spraying its melt into silicone oil. Two kinds of typical macrosegregation structures were obtained in the dispersed alloy spheres: core/ shell structure and crescent structure. Based on the estimated temperature field inside the alloy spheres, the velocities of thermal Marangoni, solutal Marangoni, and Stokes motions of the Bi-rich minor droplets were calculated. Analysis shows that surface segregation, Soret effect, thermal Marangoni motion, solutal Marangoni motion, and Stokes motion play a key role in the formation of Al/Bi-Sn core/shell structure. If the liquid alloy spheres solidify on the condition that the radius of the Bi-rich minor droplets is smaller than a critical value, it will form Al/Bi-Sn core/ shell structure, while the crescent structure will be formed when the liquid alloy spheres frozen on the condition that the radius of the Bi-rich minor droplets exceeds the critical value.

The effect of Cu addition on the liquid phase separation and macrosegregation of Fe0·42Sn0·58 immiscible alloy was investigated based on thermal analysis, microstructural observations, thermodynamic and dynamic calculations. By increasing the Cu content, a structure with drastically diminished or even free of macrosegregation was realised. It revealed that Cu alloying has reduced the Gibbs free energy of mixing and temperature dependent coefficient of interfacial tension of liquids, thus depressing not only the frequency of collision and coagulation of the minor phase globules but also the liquid phase separation. As a viable and convenient means, alloying shows promise in obtaining homogeneous structure of immiscible materials.

A series of Ti–Cu–Ni alloys with Ti content as high as 50–70 at. % expected to possess potential high glass-forming ability (GFA) was designed according to the ε criterion (Xia, M. X., Zhang, S. G., Ma, C. L., and Li, J. G., “Evaluation of Glass-Forming Ability for Metallic Glasses Based on Order-Disorder Competition,” Appl. Phys. Lett. Vol. 89, 2006, pp. 091917-1–091917-3) and were prepared by melt spinning and suck casting methods. The samples were examined by X-ray diffractometry, differential scanning calorimetry, optical microscopy, scanning electronic microscopy, and quasistatic compression test. The GFA of the melt-spun ribbons is enhanced with increasing ε. Ti58Cu32Ni10 alloy with the maximum designed ε value of 0.542 exhibits best GFA with a glass transition temperature of 627 K and a wide supercooled liquid region of 45 K. However, this alloy failed to form a fully glassy rod of 1 mm in diameter. Room temperature compression tests reveal that the 1 mm diameter Ti58Cu32Ni10 glass composite exhibits work-hardening characteristic, with ultimate compressive stress of 2418 MPa, yielding stress σ0.2 of 1448 MPa and about 7.8 % plastic strain. The combination of high strength and ductility was attributed to a dendritic TiCu(Ni) network embedded in the hard glass matrix.

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