Tailoring of materials with gradient of phases distribution obtaining by centrifugal compaction process
Marcin Rozmus, Władimir Mitiuszew, Lucyna Jaworska, Natalia Rylko 1, 3 Instytut Zaawansowanych Technologii Wytwarzania, ul. Wrocławska 37a, 30-011 Kraków, Poland 2, 4 Akademia Pedagogiczna, Instytut Techniki, ul. Podchorążych 2, 30-084 Kraków, Poland
Quarterly No. 1, 2008 pages 64-69
DOI:
keywords: diamond-Ti3SiC2 composite, functionally graded materials, high speed centrifugal compaction process, HCP, algorithm to describe sedimentation process
abstract The polycrystalline diamond PCD compacts are a round disks composite of a thin layer of sintered polycrystalline diamond bonded to a cemented tungsten carbide substrate. Commercially available PCD are usually made by high pressure sintering diamond powders with the cobalt bonding phase. The existence of cobalt promotes the graphitisation process of diamond. The differential thermal expansion of PCD layer and tungsten carbide substrate may result in residual stresses and next, delamination of material. Modification properties of these materials is possible using suitable kind of the bonding phase material, for example the ceramics Ti3SiC2 material, which is exhibiting pseudoplastics behaviour. The aim of the research was execution of mathematical calculations of the phases distribution for the phase graded diamond - Ti3SiC2 compacts which were verified with phases distribution in compacts after the high pressure - high temperature sintering process. An algorithm to describe sedimentation of the group of spherical particles of different sizes and different materials was proposed. Main calculations for this system and for real conditions of the high-speed centrifugal compaction process are made using the Barnea-Mizrahi equation. Deposition process for diamond - Ti3SiC2 was carried out using the ultra centrifuge UP 65M with rotational speed of 20 000 rpm. Particle size distribution for the diamond and Ti3SiC2 powders were measured using Shimadzu apparatus. Hardness distribution for diamonds composite with phase composition gradient was measured and compared to the concentration of diamond and carbide W for diamond and Ti3SiC2 powders dependence on distance.