Creep of fine wires of powder metallurgical tungsten

Abstract

The creep behaviour of fine wires of pure powder metallurgical tungsten was studied over the temperature range 2100–3100°C. It was found that the steady-state creep rate is given by

This result differs substantially from other reported work performed on specimens of larger diameter of polycrystalline pure tungsten. The difference is due to the fact that in the fine wire specimens numerous grain boundaries traverse the entire diameter. Creep can therefore take place by grain boundary sliding in these samples without the necessity of extensive grain deformation as is required for larger specimens where the grain size is much smaller than the sample diameter.