The effects of a reciprocating extrusion process on the friction and wear behaviors of AA 6061/SiC composites
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Mehmet Baki Karamış Erciyes University, Department of Mechanical Engineering, 38039 Kayseri, Turkey (Received 19 November 2015; accepted 5 January 2016)
The friction and wear behaviors of reciprocatingly extruded AA 6061–SiC composites form the focal point of this study. To find the optimum way for refining the grains of the matrix, reciprocating extrusion (RE), as a deformation processes, is conducted and found to be feasible. Accordingly, RE has been applied on SiC particles reinforced AA 6061 matrix composite. Using the RE passes as a base, wear behaviors of the composites have been investigated at ambient temperature under dry and lubricated forms. Optical microscopy, transmission electron microscopy and scanning electron microscopy techniques were used to reveal the effect of the RE passes on the microstructure of the materials. As a result, it is found that there is a clear relationship between the weight loss, wear resistance and hardness of the samples. As the load and the number of passes increase, the weight loss in the samples increases. The worn surfaces of the reinforced composites have commonly adhesive and abrasive type of wear.
I. INTRODUCTION
Reciprocating extrusion (RE) is one of the finest severe plastic deformation (SPD) processes for developing mechanical features and eliminating the pores in the structures of aluminum matrix composites (AMCs).1,2 The researches have focalized on featuring the microstructure and the tribological properties of AMCs via different SPD processes.3 The effects of RE processing on the microstructures and mechanical properties of various nonferrous composites have been examined to develop new ways to refine grains of these materials.4 Metal matrix composites (MMCs) have been widely used in aeronautical aerospace and automotive industries owing to their large elastic modulus, improved strength, low wear rate, easy fabrication, and low cost.5,6 Experimental results indicated considerable improvement in AMC hardness and wear resistance by adding 1.5 wt% graphite content (G) and 10 h of milling, due to homogenous distribution of the reinforcement particles in the Al-based composite. It has been found that abrasion is the dominant wear mechanism in all extruded composites, whilst a combination of adhesion and delamination seems to be the governing mechanism for the aluminum alloy.6 The paper presents the results obtained from tribological tests of aluminum composite material
Contributing Editor: Jürgen Eckert a) Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2016.10
containing 20% SiC. It has been demonstrated that SiC reinforced composite is characterized by lower wear in comparison to the matrix and that adhesive and abrasive wear were the dominant phenomena during the tests.7 The wear tests demonstrated that AA 6061 composite shows a perfect combining of wear rates and friction coefficient compared to AA 6061 alloy.8 Recently, mechanical properties and tribological behavior of nanostructured AA 2024 alloy have been investigate
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