α-Si3N4 içeren alüminyum matrisli kompozit malzeme üretimi ve özelliklerinin araştırılması

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Thesis Type: Postgraduate

Institution Of The Thesis: Gazi University, Fen Bilimleri Enstitüsü, METAL EĞİTİMİ ANABİLİM DALI, Turkey

Approval Date: 2004

Thesis Language: Turkish

Student: ÖZGÜR ÖZKÖK

Supervisor: HALİL ARIK

Abstract:

In this study, Al based composite materials containing various amount of a- Sİ3N4 was produced by powder metallurgy technique. To prepare mixture of Al and a-Sİ3N4 powders two different mixing processes were carried out. One batch was milled in a horizontal ball mill for 5 hours and the other was mechanically alloyed in a high energy ball mill for 5 hours. Mixed powders were compacted under 1000 MPa pressure to produce standard transverse rupture test blocks with dimension of 6.35x12.70x31.70 mm. Compacted samples were then sintered at 620; 640; 660; and 680 °C for 2 h under Ar atmosphere in a tube furnace. The mechanical properties of the composite specimens were determined by measuring the density, hardness and transverse rupture strength values. Microstructures were investigated by using optical and SEM microscopes. The results showed that, more homogenous distribution of 01-Sİ3N4 were obtained in Al matrix by mechanical alloying technique compared to those found in classical mixing method. As a result of homogenous dispersions of a- Sİ3N4 particles high hardness and transverse repute strength values were obtained on the samples produced by mechanical alloying technique.Key Words : Mechanical alloying, Composites, Aluminum, Sİ3N4