Student:	Temel VAROL
Supervisor:	Doç.Dr. Aykut ÇANAKÇI
Department:	Makine Mühendisliği
Institution:	Graduate School of Natural and Applied Sciences
University:	Karadeniz Technical University Turkey

Title of the Thesis:	The Fabrication and Characterizaytion of Nano Particle Reinforced-Copper Matrix Functionally Graded Electrical Contact Materials
Level:	Ph.D.
Acceptance Date:	15/1/2016
Number of Pages:	231
Registration Number:	Di1112

Summary:

The aim of the present work was to study the production of nano particle reinforced Cu matrix

functionally graded electrical contact materials using powder metallurgy method and to investigate

the relationship of the particle type and particle content with physical properties, mechanical

properties, wear resistance and arc erosion behavior of fabricated electrical contact materials. The

effects of reinforcement type and weight percentage (wt%) on the physical and mechanical

properties of the the composites were determined by measuring the density, electrical conductivity

and hardness values. At the second step, the nanocomposites providing the best conductivity, the

best wear resistance and the best contact performance was used for the production of functionally

graded electrical contact materials. The electrical conductivity is in the range of 78.5-61.5 IACs for

sintered Cu-graphene nanosheets nanocomposites. Hardness of Cu-nanographite and Cu-carbon

nanotube nanocomposites is lower than that of the Cu-graphene nanosheet nanocomposites. It was

observed that the wear resistance of Cu-based nanocomposites has been improved significantly

when graphene nanosheet particles are used as reinforcement particles. Compared to monolithic

copper and Cu-Carbon nanotube samples, Cu-nanographite and Cu-graphene nanosheet

nanocomposites show the remarkable improvement on the arc erosion behavior due to higher

electrical conductivity and acceptable wear resistance. Microstructure and properties of functionall

graded materials shows that the gradation resulted in a remarkable enhancement of electrical

conductivity, hardness, wear resistance and arc erosion properties. The electrical conductivity of

FGM samples was changed from 73 IACs to 90 IACs along the thickness. The Brinell hardness of

FGM samples was changed from 29 IACs to 34 IACs along the thickness. Wear rate and arc

erosion rate were decreased by using two and three layers FGM.

Keywords: Functionally Graded Materials, Powder Metallurgy, Nanocomposite