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In the present study, two kinds of bulk metallic glasses (Zr55Cu30Al10Ni5 and Cu46Zr42Al7Y5) with high strength and no plastic strain were adopted as matrixes. Both of them were reinforced by ductile crystalline TiNb with the same volume fraction and particle size. The compression results showed that the plastic strain of TiNb/Zr55Cu30Al10Ni5 composite was higher 292% than that of TiNb/Cu46Zr42Al7Y5 composite. It should be related to the fracture toughness of the glassy matrix. For the glassy matrix with high toughness, the formation of shear bands and micro-crack at the front of the crack reduced the energy of main crack development. It resulted in a large plastic strain. On the other hand, for the brittle metallic glassy matrix, crack developed quickly through the cross section so that no more shear bands was formed. It resulted in the failure of the sample with smaller plastic strain. [ABSTRACT FROM AUTHOR]

A new type of magnesium alloy based on Mg–Zn–Si system has been developed for automobile application. The solidification process, microstructure, mechanical properties and creep resistance of the new alloy have been studied. Results show that the Mg–6Zn–1Si alloy has good comprehensive mechanical properties and its creep resistance is better than that of AZ91 alloy. Proper additions of Ca were found to be efficient in refining the microstructure of Mg–6Zn–1Si alloy. A morphological change in Mg2Si particles from coarse Chinese script shape to a small polygonal type was also observed. The modification mechanism of Ca is polygonal type Mg2Si particles nucleate from CaSi2 particles. Such improved microstructure of the Mg–6Zn–1Si–0.25Ca alloy results in significant improvement in tensile properties and creep resistance as compared to the Mg–6Zn–1Si base alloy. [Copyright &y& Elsevier]