Synthesis of large-size nanocrystal-toughened Cu-based bulk metallic glasses with excellent plasticity by controlling solidification

1)Cu-Zr-Al-Ag合金的非晶形成能力显著提高。在Cu-Zr-Al-Ag块体非晶合金中，Ta颗粒（40μm）均匀分布，直径为2- 5 mm。该复合材料表现出高强度和不寻常的塑性。Ta颗粒的存在，为多个剪切带的形成提供了种子，并阻断了剪切带的传播，使剪切带呈网状均匀分布。2）采用铜模铸造法制备了含有5- 10 nm纳米晶的大尺寸Zr-Cu-Al-Fe块体非晶合金。复合材料表现出高屈服强度和大塑性的组合。阐明了这种新型块体非晶复合材料具有大塑性的机理。

1) Glass-forming ability of Cu-Zr-Al-Ag alloys was significantly enhanced by the composition optimum. The Ta particles (40μm) homogenously distributed the Cu-Zr-Al-Ag bulk glassy alloys with diameters of 2-5mm were synthesized. The composites showed high strength and unusual plasticity. Ta particles seed the initiation of multiple shear bands and block the shear band propagation, leading to a net-like homogeneous distribution of the shear bands.2) The large-size Zr-Cu-Al-Fe bulk glassy alloys containing nanocrystals with size of 5-10nm were obtained by copper mold casting. The composites exhibited a combination of high yield strength and large plasticity. The mechanism for the large plasticity of the new bulk glassy composites is elucidated.