Investigation of weldability of Al-Si3n4 composite materials by diffusion welding

INVESTIGATION OF WELDABILITY OF Al-Si3N4 COMPOSITEMATERIALS BY DIFFUSION WELDING(M.Sc. Thesis)BRAH M OKAN ERDENGAZI UNIVERSITYINSTITUTE OF SCIENCE AND TECHNOLOGYDECEMBER 2005ABSTRACTIn this study, Al powders containing 5%, 10% and 15% wt (Si3N4) siliconnitride were mechanically alloyed in a high energy attritor for 2 h. Mechanicallyalloyed powders were compacted at constant pressing pressure (500 MPa) toproduce block specimens with dimensions Ø10 x 15 mm. Specimens were thensintered at constant temperature (650 ºC) for 4 h under argon atmosphere in atube furnace. Sintered specimens were welded different temperatures (620, 630,640) ºC and different times (60, 90 and 120) min. under 2,5 MPa pressure bydiffusion welding. After welding process, specimens were treated cutting test asmechanical test. Cutting test valves optained main material and weldedspecimens were compared each other. It was observed that composite washomogeneous structure and low pores quantity in optic microscope studies. Itwas determined that the best result occured at diffusion welding made at 640 ºCfor 2 h acoording to results obtained cutting test.Science Code : 710Key Words : Diffusion Welding, Composite, Powder MetallurgyPapes : 99Supervisors : Assoc. Prof. Dr. Halil ARIK