Laboratory of Metal Physics and Technology, Department of Materials, ETH Zurich, 8093, Zurich, Switzerland.
School of Materials Science and Engineering UNSW Australia, NSW, 2052, Australia.
Sci Rep. 2017 Jun 13;7(1):3400. doi: 10.1038/s41598-017-03643-7.
Magnesium-based bulk metallic glasses (BMGs) exhibit high specific strengths and excellent glass-forming ability compared to other metallic systems, making them suitable candidates for next-generation materials. However, current Mg-based BMGs tend to exhibit low thermal stability and are prone to structural relaxation and brittle failure. This study presents a range of new magnesium-precious metal-based BMGs from the ternary Mg-Ag-Ca, Mg-Ag-Yb, Mg-Pd-Ca and Mg-Pd-Yb alloy systems with Mg content greater than 67 at.%. These alloys were designed for high ductility by utilising atomic bond-band theory and a topological efficient atomic packing model. BMGs from the Mg-Pd-Ca alloy system exhibit high glass-forming ability with critical casting sizes of up to 3 mm in diameter, the highest glass transition temperatures (>200 °C) of any reported Mg-based BMG to date, and sustained compressive ductility. Alloys from the Mg-Pd-Yb family exhibit critical casting sizes of up to 4 mm in diameter, and the highest compressive plastic (1.59%) and total (3.78%) strain to failure of any so far reported Mg-based glass. The methods and theoretical approaches presented here demonstrate a significant step forward in the ongoing development of this extraordinary class of materials.
镁基块状金属玻璃 (BMG) 与其他金属系统相比具有较高的比强度和优异的玻璃形成能力，因此成为下一代材料的候选材料。然而，目前的镁基 BMG 往往表现出较低的热稳定性，容易发生结构弛豫和脆性失效。本研究提出了一系列新的三元 Mg-Ag-Ca、Mg-Ag-Yb、Mg-Pd-Ca 和 Mg-Pd-Yb 镁贵金属基 BMG，其镁含量大于 67at%。这些合金是通过利用原子键带理论和拓扑有效原子堆积模型设计出高延展性的。Mg-Pd-Ca 合金系的 BMG 具有高的玻璃形成能力，临界铸造尺寸可达 3mm 直径，是迄今为止报道的任何基于镁的 BMG 中最高的玻璃转变温度（>200°C），并具有持续的压缩延展性。Mg-Pd-Yb 族的合金具有高达 4mm 直径的临界铸造尺寸，以及迄今为止报道的任何基于镁的玻璃中最高的压缩塑性（1.59%）和总应变（3.78%）失效。本文提出的方法和理论方法在这种特殊材料的不断发展中迈出了重要的一步。
