CHARACTERIZATION OF SILICON CARBIDE PARTICULATE REINFORCED SQUEEZE CAST ALUMINUM 7075 MATRIX COMPOSITE A THESIS SUBMITTED TO THE GRADUATE SCHOOL OF NATURAL AND APPLIED SCIENCES OF MIDDLE EAST TECHNICAL UNIVERSITY BY HAMDİ SENCER YILMAZ IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN METALLURGICAL AND MATERIALS ENGINEERING AUGUST 2004