Compaction of the diamond – Ti3SiC2 graded material by the high – speed centrifugal compaction process

摘要

Purpose: Sedimentation of particles in a viscous fluid is a main physical problem in fluid mechanics. Sedimentation is benchmark of one of the technica; methods to produce the functionally graded materials (FGM) with a continuous spatial change of mechanical properties. 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. Design/methodology/approach: In this paper, we construct a mathematical model of FGM basing on the modifications of the Stokes formula. We proposed an algorithm to describe sedimentation of the group of spherical particles of different sizes and different materials. Main calculations for this system and real conditions of the highspeed centrifugal compaction process are made using the Barnea-Mizrahi equation. Deposition process was carried out using the ultra centrifuge UP 65M with rotational speed of 15000 to 25000 rpm. Particle size distribution for the diamond and Ti3SiC2 powders were measured using Shimadzu apparatus. Findings: The results of calculations and microscopic analysis are compared. The obtained results of mathematical calculations demonstrate that for the considered diamond-Ti3SiC2 suspensions the obtained compact has the structure of the laminate what confirmed microscopic analysis. Practical implications: The mathematical simulations using our algorithm show that it is possible to obtain continuous concentrations of the both materials with appropriate initial suspensions. Thus our method allows to obtain graded materials. Originality/value: This mathematical model gives possibility of use to describe sedimentation of the group of spherical particles different materials and different sizes.