Rate of Crystal Growth in Drawn Tungsten Wires as a Function of Temperature

This is the authors' abstract. We don't add key points for this paper.

Large single crystals can be grown in ``218'' and similar tungsten wires by vacuum heating at a constant temperature in the range 1900°K to 2200°K. The growth can be followed by observation of the thermionic emission pattern, using a cylindrical electron-projection tube with a fluorescent screen. The rate of growth is found to increase with temperature according to an exponential law. Crystal growth is slower in wires drawn to smaller diameter; this can be explained by the small grain hypothesis. The perfection of crystals is discussed.