Wear Characteristics of Chilled Aluminum Alloy Reinforced With Nano ZrO2 Metal Matrix Composites (NMMCs) for Automotive Applications
G. Balakumar, Joel Hemanth
Transactions on Machine Design, Vol. 4, No. 2, 2016.
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Abstract:
This paper aims at development of aluminum alloy (LM 13) reinforced with varying wt.% (3 to 15wt.% in steps
of 3) of nano-ZrO2 particles(mesh size 70-90nm) cast using chilling technique which remains an attractive choice among all
the solidification processing routes due to its capability of bringing together the advantages of both stir casting and
directional solidification. The developed NMMCs and the as cast matrix alloy were hot extruded in a hydraulic press at
250oC. Investigations of microstructural characterization reveal uniform distribution of reinforcement with interfacial
integrity between matrix and the reinforcement. Dry sliding wear behavior of the developed NMMCs and matrix alloy was
investigated using pin-on-disc apparatus under varying loads. The results exhibit a limiting load known as transitional load
beyond which the material (whether matrix alloy or NMMCs) experiences â€˜seizureâ€™. The transitional load of the developed
NMMCs was much higher than matrix alloy. It was also observed that the specific wear rate significantly decreased with
increase in reinforcement content but remarkably increases with increase in applied load and sliding distance. However the
coefficient of friction registered decreasing trend with increase in sliding distance and reinforcement additions. SEM
photograph of worn surfaces of developed NMMCs and matrix alloy reveal delamination of MML (mechanically mixed layer)
attributing for seizure.