Cold uniaxial compaction of Ti-containing powders: Rheological aspects

Pre-compaction of powder mixtures by cold pressing is being widely used in numerous areas of modern science and technology, including SHS. Normally, the process is being carried out at constant pressure ( P = const), so that the calibration plot in the coordinates pressure‐density (porosity) is obtained in a series of experiments at different P [1]. In this communication, we suggest to determine the calibration plot of a given press facility in one experimental run performed at a constant velocity of plunger feed V p . As a model, we used Ti + B and Ti + C + Ni powder mixtures. These mixtures were used as green mixtures in SHS extrusion of electrodes for electrospark alloying [2]. Powder compositions were as follows: 20 wt % Ti + 80 wt % B and 56 wt % Ti + 14 wt % C + 30 wt % Ni. Experiments were carried out in an INSTRON apparatus at constant V p (5 mm min ‐1 ) at a load up to 10 t (determined with an accuracy of 1%).