Search

Bulk metallic glass composites containing in-situ formed β-Ti/Zr phases (β-type BMGCs), which exhibit a good combination of strength and plasticity, were generally developed by adding β-stabilizers, such as Nb, Ta, V, etc., into Ti/Zr-based bulk metallic glasses (BMGs). In this work, an iteration method is proposed to develop β-type BMGCs from Ti/Zr-based BMGs, and the compositions of BMGCs can be designed by “the composition of in-situ formed β phase (the iterative variable) + the composition of BMG”. Due to the fast elemental diffusions between the β phase and the (supercooled) liquid phase, the iteration method can develop β-type BMGCs in which both phases can maintain a mutual (metastable) equilibrium during solidification. The procedures of the iteration method and its underlying thermodynamic and kinetic principles are discussed, and a Zr 56.9 Ti 18.8 Cu 7.4 Ni 5.7 Be 11.3 BMGC was developed from Vitreloy 1 by using the iterative method. As compared with β-type BMGCs developed by the conventional method, β-type BMGCs developed by the iteration method have two advantages: (i) the good glass-forming ability of the initial BMGs can be largely inherited by the glassy matrices in BMGCs; (ii) without adding β-stabilizers, the in-situ formed β phases are more likely to be metastable. The current iteration method is of scientific significance on improving plasticity of Ti/Zr-based BMGs and developing new β-type BMGCs. [ABSTRACT FROM AUTHOR]

Addition of a small amount of La and Co enhances the stabilization of supercooled liquid and glass-forming ability (GFA) of an Al 85 Ni 7 Er 8 metallic glass. The Al 85 Ni 5 Co 2 Er 6 La 2 alloy exhibits large supercooled liquid region of 40 K, high GFA with a critical thickness of 450 μm, and the viscosities on the order of 10 7 −10 9 Pa s in the supercooled liquid state. The Al-based glassy nano-scale patterns were formed by imprinting, indicating its good thermoplastic formability. The possible mechanism for the improvement of the supercooled liquid stability of the Al Ni Er alloy by addition of La and Co elements was discussed in terms of the crystallization behavior. [ABSTRACT FROM AUTHOR]