Room Temperature Viscous Flow of Amorphous Silica Induced by Electron Beam Irradiation

The increasing use of oxide glasses in high-tech applications illustrates the demand of novel engineering techniques on nano- and microscale. Due to the high viscosity of oxide glasses at room temperature, shaping operations are usually performed at temperatures close or beyond the point of glass transition T-g. Those treatments, however, are global and affect the whole component. It is known from the literature that electron irradiation facilitates the viscous flow of amorphous silica near room temperature for nanoscale components. At the micrometer scale, however, a comprehensive study on this topic is still pending. In the present study, electron irradiation inducing viscous flow at room temperature is observed using a micropillar compression approach and amorphous silica as a model system. A comparison to high temperature yielding up to a temperature of 1100 degrees C demonstrates that even moderate electron irradiation resembles the mechanical response of 600 degrees C and beyond. As an extreme case, a yield strength as low as 300 MPa is observed with a viscosity indicating that T-g has been passed. Those results show that electron irradiation-facilitated viscous flow is not limited to the nanoscale which offers great potential for local microengineering.

Automated summary

The increasing use of oxide glasses in high-tech applications demonstrates the demand for novel engineering techniques on nano- and microscale. Shaping operations of oxide glasses at room temperature usually require high temperatures close or beyond the point of glass transition T-g. However, electron irradiation has been found to facilitate the viscous flow of amorphous silica at room temperature, offering potential for local microengineering.