Computer-modelled deformation mechanism maps for hot uniaxially pressed Bi-2223 superconductor

A deformation mechanism map represents the densification behaviour of a green powder body. A map is created by evaluating the rate-equations for five types of densification mechanisms: yield, boundary diffusion, volume diffusion, power-law creep, and Nabarro Herring creep. These rates are summed where appropriate and integrated to give the density at a given pressure, temperature and time; this can then be plotted on a map. Such maps have been created for hot-pressed Bi-2223, using the HIP 6.0 computer software. Four temperature density deformation maps were created at different pressing pressures and for two types of powder: a solid-state reacted powder and a pyrolysed organic precursor powder. The resulting maps are compared and discussed in relation to a set of experimental results.