The aluminum based composites are increasingly being used in the transport, aerospace,
marine, automobile and mineral processing industries, owing to their improved strength,
stiffness and wear resistance properties. The widely used reinforcing materials for these
composites are silicon carbide, aluminum oxide and graphite in the form of particles or
whiskers. The ceramic particles reinforced aluminum composites are termed as new generation
material and these can be tailored and engineered with specific required properties for specific
application requirements. Particle reinforced composites have a better plastic forming capability
than that of the whisker or fiber reinforced ones, and thus they have emerged as most sought
after material with cost advantage and they are also known for excellent heat and wear
resistance applications. In this paper it is aimed to present the experimental results of the studies
conducted regarding hardness, tensile strength and wear resistance properties of Al6061-SiC
and Al7075-Al2O3 composites. The composites are prepared using the liquid metallurgy technique, in which 2-6 wt. %’age of particulates were dispersed in the base matrix in steps of 2. The obtained cast composites of Al6061-SiC and Al7075-Al2O3 and the castings of the base alloys were carefully machined to prepare the test specimens for density, hardness, mechanical, tribological tests and as well as for microstructural studies as per ASTM standards. The SiC and Al2O3 resulted in improving the hardness and density of their respective composites. Further, the
increased %’age of these reinforcements contributed in increased hardness and density of the
composites. The microphotographs of the composites studied revealed the uniform distribution of the particles in the matrix system. The experimental density values were agreed with that of the
theoretical density values of the composites obtained using the rule of mixture for composites.
The dispersed SiC in Al6061 alloy and Al2O3 in Al7075 alloy contributed in enhancing the tensile strength of the composites. The wear factor K obtained using computerized pin on disc wear tester with counter surface as EN31 steel disc (HRC60) and the composite pin as
specimens, demonstrated the superior wear resistance property of the composites.
References
[1]
J. Gilbert Kaufman “Properties of Aluminum Alloys; Tensile, Creep, and Fatigue Data at High and Low Temperatures”, ASM International 2002.
[2]
ASM handbook of Composites, Volume 21.
[3]
G.Straffelini, F.Bonollo, A.Tiziani, “Influence of matrix hardness on the sliding behavior of 20 vol% Al2 O3 -particulate reinforced 6061 Al metal matrix composite”, Wear 211 (1997) 192-197.
[4]
Martin, J. Rodriguez, J. Llorca, “Temperature effects on the wear behavior of particulate reinforced Al-based composites”, Wear 225–229 (1999) 615–620.
[5]
Szu Ying Yu, Hitoshi Ishii, Keiichiro Tohgo, Young Tae Cho, Dongfeng Diao, “Temperature dependence of sliding wear behavior in SiC whisker or SiC particulate
reinforced 6061 aluminum alloy composite”, Wear 213 (1997) 21-28.
Liang, Y. N., Ma, Z. Y., Li, S. Z., Li, S. and Bi, J., “Effect of particle size on wear behaviour of SiC particulate-reinforced aluminum alloy composites”, Journal of Materials Science Letters, 1995, 14, 114- 116.
[8]
Basavarajappa, S., Chandramohan, G., Subramanian, R. and Chandrasekar., “Dry sliding wear behaviour of Al2219/SiC metal matrix”, Materials Science-Poland, 2006, 24(2/1), 357-366.
[9]
Basavarajappa S. and Chandramohan G., “Wear studies on metal matrix composites- Taguchi approach”, Journal of Material Science and Technology, 2005, 21(6), 845- 850.
[10]
Y. Reda, R. Abdel-Karim and I. Elmahallawi “Improvements in mechanical and stress corrosion cracking properties in Al-alloy 7075 via retrogression and reaging” Materials Science and Engineering: A, Volume 485, Issues 1-2, 25 June 2008, Pages 468-475.
[11]
R. Clark, Jr, B. Coughran, I. Traina, A. Hernandez, T. Scheck, C. Etuk, J. Peters, E.W. Lee, J. Ogren and O.S. Es-Said “On the correlation of mechanical and physical properties of 7075-T6Al alloy” Engineering Failure Analysis, Volume 12, Issue 4, August 2005, Pages 520-526.
[12]
S. W. Kim, D. Y. Kim, W. G. Kim and K. D. Woo, “The study on characteristics of heat treatment of the direct squeeze cast 7075 wrought Al alloy”, Materials Science and Engineering A, Volumes 304-306, 31 May 2001, Pages 721-726.
[13]
Rupa Dasgupta and Humaira Meenai, “SiC particulate dispersed composites of an Al– Zn–Mg–Cu alloy: Property comparison with parent alloy”, Materials Characterization, Volume 54, Issues 4-5, May 2005, Pages 438-445.
[14]
T. J. A. Doel and P. Bowen, “Tensile properties of particulate-reinforced metal matrix composites Composites Part A”, Applied Science and Manufacturing, Volume 27, Issue 8, 1996, Pages 655-665.
[15]
K. Komai, K. Minoshima and H. Ryoson, “Tensile and fatigue fracture behavior and water-environment effects in a SiC-whisker/7075-aluminum composite”, Composites Science and Technology, Volume 46, Issue 1, 1993, Pages 59-66.
[16]
M.D. Bermudeza, G. Martinez-Nicolas, F.J. Carrion, I. Martinez-Mateo, J.A. Rodriguez, E.J. Herrera, “Dry and lubricated wear resistance of mechanically-alloyed aluminiumbase sintered composites”, Wear 248, 178–186, 2001.
[17]
M.R. Rosenberger, C.E. Schvezov, E. Forlerer, “Wear of different aluminum matrix composites under conditions that generate a mechanically mixed layer”, Wear 259, 590–601, 2005.
[18]
L.J. Yang “A test methodology for the determination of wear coefficient” Wear 259, 1453–1461, 2005.
[19]
J.M. Wu, Z.Z. Li, “Contributions of the particulate reinforcement to dry sliding wear resistance of rapidly solidified Al-Ti alloys”, Wear 244, 147–153, 2000.
