Preparation  and Mechanical Characterization of Cu-Al2O3 Functionally Graded Material for electrical contact applications

Raheem. K. Abid Ali, Abdul; Hatem Kadhim, Roaa

	Preparation and Mechanical Characterization of Cu-Al2O3 Functionally Graded Material for electrical contact applications
Journal of University of Babylon
Article 1, Volume 25, Issue 4, 2017, Pages 1339-1451
Authors
Abdul Raheem. K. Abid Ali; Roaa Hatem Kadhim
Abstract
In this study, five-layered stepwise Cu/Al2O3 as functionally graded materials have been prepared from copper powder with with five percentage of alumina powder as (5 ,10 ,20 ,30 and 40 Wt%) by using powder metallurgy technique. Mixing of copper (34.32 µm) and alumina (1.439 µm) powders for two hours and then several disk sample with dimensions (14mm diameter and 10 thickness) have been compacting at different compacting stresses (550, 650 and 750 MPa). However, sintering of specimens for three hours at 850 under vacuum about has been achieved. The Porosity and density before and after sintering have been calculated. X-ray diffraction analysis showed that tests before and after sintering is similar, there is no new phase formed after sintering. Scanning electron microscopy technique is used to characterize the surface of each layer. Hardness test showed slight linear graded microhardness across the layers without any obvious jumps throughout the thickness. Pin on disc method have been used in determining the wear or material removal of prepared FGM samples. In addition, it was examined thermal conductivity and the electrical resistance have been done in preparing samples from composite and functionally graded material. From the experimental results, it is clear that hardness results change in each layer by producing FGM according to the percentage of the harder constituent (i.e. Al2O3) from 53 to 113 Hv. While Thermal conductivity decrease with the increasing addition weight percentage for α-Al2O3. And Electrical resistance increased when alumina content increased for (5% to 40%). Wear rate improved with the increasing additive percentage of alumina from 0.507 for layer 1 to 0.15 for layer five at 15N and 25 min. Smoothly gradual change of the composition in the Cu/Al2O3 FGM can eliminate the microscopic interface, such as a result as that traditional Cu-Al2O3 joint
Keywords
Functionally graded materials; powder metallurgy technique; Material characterization of FGM

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