Migration of grain boundaries in Zn

The results of investigations of grain boundary migration in zinc bicrystals (99.995%) are presented. An in situ technique for the observation and continuous recording of boundary migration was applied for measurement of both magnetically and curvature driven boundary motion. Symmetrical and asymmetrical 〈101¯0〉 and 〈112¯0〉 tilt grain boundaries with rotation angles in the range 60-90° were studied. For magnetically driven boundaries the absolute grain boundary mobility was determined. The boundary motion was measured in the regime between 330 °C and 415 °C, and the corresponding migration activation parameters were determined. The results revealed a pronounced misorientation dependence of grain boundary mobility in the investigated angular range. Migration of tilt grain boundaries in Zn was also found to depend on boundary inclination. The migration activation parameters for the investigated curved 〈101¯0〉 tilt boundaries moving under a capillary driving force were distinctly different from the corresponding parameters obtained for magnetically driven 〈101¯0〉 tilt boundaries with similar misorientation angle. The migration activation parameters of all investigated boundaries comply with the compensation law, i.e. there is a linear relationship between the activation enthalpy and the logarithm of the pre-exponential mobility factor.