Alumina based super-plastic ceramics with enhanced ductility for improved machineability

摘要

A super-plastic ceramic with an alumina base containing zircon and a spinel of magnesia/alumina is characterised in that:- a) the total quantity of the zircon phase, the magnesia/alumina spinel phase and the alumina phase is 90% or more by volume; b) the average crystalline diameter after firing is 2.5 microns or less for the magnesia/alumina spinel phase and the alumina phase and 1.0 microns or less for the zircon phase; and c) the ductility under traction is 200% or more at a deformation speed of 1.0 asterisk 10-4s-1 or more at a temperature of 1300 deg C or more.