Production of particulate magnesia reinforced al matrix composite by vacuum infiltration method and investigation of their properties

PRODUCTION OF PARTICULATE MAGNESIA REINFORCED ALMATRIX COMPOSITE BY VACUUM INFILTRATION METHOD ANDINVESTIGATION OF THEIR PROPERTIES(Ph.D. Thesis)Recep ÇALINGAZI UNIVERSITYINSTITUTE OF SCIENCE AND TECHNOLOGYJune 2006ABSTRACTComposite materials are one group of engineering materials that weredeveloped in last century and have being used in an increasing ratio. There aredifferent types of composite materials and production methods and new type ofthese materials and production methods have being developed. One type ofthese materials is metal matrix composites (MMC). In metal matrix composites,light metals such as Mg, Ti and especially Al are used as matrix. As forreinforcement, some ceramics and refractories such as Al2O3, SiC, SiO andMgO have being commonly used. Different methods such as casting, powdermetallurgy, in-situ and infiltration are used for composite production.Pressureless, pressure and vacuum infiltration techniques are carried out forinfiltration techniques. In this study, effect of parameters in production of Almatrix MgO reinforced composite by vacuum infiltration, has been investigated.Particle size, infiltration temperature and duration, reinforcement volume ratio,vacuum value and chemical and physical properties of matrix andreinforcement are important parameters in infiltration. Effects of theseparameters on microstructure, fracture strength and hardness of compositehave been determined. It has been determined that increasing infiltrationtemperature and duration, reinforcement particle size, vacuum value and Mgcontent of matrix increased infiltration distance and increasing reinforcementvolume ratio showed an adverse effect. Infiltration duration of 3 min is enoughfor given infiltration height in adequate conditions. It has been also found thatporosity of composite increases with the conditions that have adverse effects oninfiltration. Fracture strength of composite has been increased with increasingparameters except for Mg content of matrix.Science Code : 626.19.01Key Words : Composites, Infiltration, MgO, AluminumPage Number : 119Adviser : Assist. Prof. Dr. Ramazan ÇITAK