PRESSURE (MPa)

1. 85 20% SiC 80 75 70 GREEN DENSITY %TD 65 60 55 Al + SiC Size Ratio d50,3 7µm + 6µm 50 1:1 0 40 80 120 160 200 7µm + 28.5µm 1:4 PRESSURE (MPa) 11µm + 6µm 1:0.625 16µm + 6µm 1:0.4 11µm + 28.5µm 1:2.5 Manufacture of SiC Composite Parts Using Powder Metallurgical MethodsAdrian Dunne, Dr. Lisa Looney and Dr. Jerry Murphy Materials Processing Research Centre, Dublin City University, Dublin 9, Ireland Introduction: To meet the very demanding mechanical requirements of many of today’s material applications Metal Matrix Composites (MMCs) have received more research attention in recent times. Traditionally PM parts made of Silicon Carbide (SiC) composite materials are manufactured using an extremely expensive processes. It has been shown that it is possible to manufacture such parts using simple, and cheap, uniaxial pressing. However the size ratio of the powders has a big effect on the final mechanical properties of the material. How can we understand and model this phenomena? Some Parts Commonly made using Powder Metallurgy Project Aims: The main aim of this project is to develop a model to describe the behaviour of the SiC composite materials as processed by PM methods with particular referance to the effects of the relative sizes of the powders used. Effect of different size combinations on Green Density Research: A literature review of all papers in the field of PM modelling has been carried out. It has been seen that many different approaches to such models exist and that the accuracy of each depends on the circumstances in which they are used. The models as constructed in this research so far are in agreement with what is seen experimentally i.e. that relative powder size (RPS) has a large effect on the porosity of the powder before compaction. This may well be part of the reason for the dependence of mechanical properties on RPS. The Stages of Powder Metallurgy Manufacturing PM PROCESSING ROUTE INVESTIGATED Uniaxial Pressing Liquid Phase Sintering Mixing (Al + SiC)