Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124, China.
Nat Commun. 2010 Jun 1;1:24. doi: 10.1038/ncomms1021.
Glasses are usually shaped through the viscous flow of a liquid before its solidification, as practiced in glass blowing. At or near room temperature (RT), oxide glasses are known to be brittle and fracture upon any mechanical deformation for shape change. Here, we show that with moderate exposure to a low-intensity (<1.8×10(-2) A cm(-2)) electron beam (e-beam), dramatic shape changes can be achieved for nanoscale amorphous silica, at low temperatures and strain rates >10(-4) per second. We show not only large homogeneous plastic strains in compression for nanoparticles but also superplastic elongations >200% in tension for nanowires (NWs). We also report the first quantitative comparison of the load-displacement responses without and with the e-beam, revealing dramatic difference in the flow stress (up to four times). This e-beam-assisted superplastic deformability near RT is useful for processing amorphous silica and other conventionally-brittle materials for their applications in nanotechnology.
玻璃通常通过液体在固化前的粘性流动来成型，这就是玻璃吹制的原理。在室温（RT）或接近室温时，氧化物玻璃是脆性的，在任何机械变形下都会发生断裂，从而改变形状。在这里，我们表明，通过适度暴露于低强度（<1.8×10（-2）A cm（-2））电子束（e-beam），在低温和应变率> 10（-4）/秒的情况下，可以实现纳米级无定形二氧化硅的显著形状变化。我们不仅在压缩时展示了纳米颗粒的大均匀塑性应变，而且还在拉伸时展示了纳米线（NWs）的超过 200%的超塑性伸长率。我们还报告了没有和有电子束时的负载-位移响应的首次定量比较，揭示了流动应力的显著差异（高达四倍）。这种室温附近的 e-beam 辅助超塑性变形对于处理无定形二氧化硅和其他传统脆性材料非常有用，可将其应用于纳米技术中。
