非晶态材料具有冻结的液体结构，但它并不像液体那样流动，反而表现出宏观脆性。在某些情况下一定的外加应力可以使非晶材料流动，这种流动的控制机制是什么？这是材料物理界重要的科学问题。最近的一些研究结果显示非晶合金的塑性流动也可以认为是应力导致的局域的玻璃转变和局域液态结构的演化。这使人们对非晶合金的韧/脆性本质，及非晶合金流动的物理本质的认识有了新的思路。是否有方法可以直接地表征这种从玻璃态向液态转变的过程？已有很多实验结果证实非晶材料（包括非晶合金）在辐照下会产生特有的、显著的各向异性塑性流动。本项目拟从系统研究不同非晶材料在辐照下流动特性及其差异入手，为理解控制非晶合金流动本质的提供重要的实验依据。同时利用离子辐照实现纳米尺度上的结构调控，也将有助于深入理解非晶合金流动以及韧/脆的本质原因。另外非晶合金在离子辐照下显著的各向异性生长特性也将使其在纳米雕刻等领域具有重要应用前景。

Glasses are liquids that have become frozen in time, but they do not flow like liquids. In contrast, they are macroscopic brittle. In some cases, a flowing state can be restored by exceeding a threshold of external force. What are the physical principles governing the melting and freezing? This is one of the 11 big physical questions in correlated matters. Recent studies reveal that the plastic flow in metallic glass can also be ascribed to stress-driving glass transition. This provides a new route for understanding the principle of the plastic flow and ductility/brittleness in metallic glass systems. Is there an approach to directly demonstrate the transition from glassy state to liquid state? Many works have proved that significant anisotropic plastic flow takes place in glassy materials (including metallic glass) under heavy ion irradiation. In this proposal, a systematic study on the viscous flow hehavior of typical metallic glass systems under ion irradiation will be conducted. This should provide valuable information on understanding the physical principle governing the plastic flow in metallic glasses. Meanwhile, we will also use ion irradiation as a tool to tailor the structure in metallic glasses in nanometer scale. This will be helpful to understanding the principle of the ductility/brittleness in metallic glasses. In addition, the anisotropic plastic flow in metallic glasses under ion irradiation may also find their way in nanotechnique, e.g. nanosculpture.