Room and High-Temperature Wear Behaviour of Al-Based MMCs against an Automotive Brake Pad

Abstract

Aluminium metal matrix composites are promising materials for automotive brake discs, and it is critical to assess their wear performance in different braking conditions. This article presents the wear behaviour of aluminium-based composites with different Al-Si matrix alloys added with nickel and copper to retain mechanical strength at high temperatures. The wear tests were conducted at room and high temperatures (250 and 400 °C) to simulate different braking conditions on a pin-on-plate tribometer. The coefficient of friction is in the range of 0.15-0.17 for all materials at room temperature. The specific wear rates of the brake pad and the disc materials indicate that material transfer occurs from the brake pad to the metal counterpart. Microscopy investigations of the wear tracks confirm the material transfer on the composites. It protects the composite surface from wear damage and maintains a stable coefficient of friction. To translate these results into real-world scenarios, the findings of this study suggest that aluminium-based metal matrix composite brake discs have a longer product lifespan compared to the grey cast iron brake discs; the brake pads for the composites would be the components to need replacement due to wear during the product life instead of the brake discs.

Keywords

aluminium / metal matrix composite / wear / friction / tribology / microscopy

Author Contributions

Conceptualization, L.L. and A.E.W.J.; methodology, L.L.; validation, L.L. and A.E.W.J.; formal analysis, L.L.; investigation, L.L.; resources, A.E.W.J.; data curation, L.L.; writing—original draft preparation, L.L.; writing—review and editing, A.E.W.J.; visualisation, L.L.; project administration, L.L.; funding acquisition, L.L. and A.E.W.J. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the Stiftelsen för kunskaps- och kompetensutveckling (KK-Stiftelsen), Sweden, through the project “Properties and formability of Al-SiCp MMCs” (ProForAl) [Prospekt, diarienr. 20201702].

Data Availability Statement

Data will be made available on request.

Acknowledgments

The authors gratefully acknowledge the ProForAl project partners: Samuel Awe at Automotive Components Floby AB, Per Jansson at Comptech i Skyllingaryd AB, Richard Westergård at Gränges Finspång AB and Carl Rudenstam at Husqvarna Group AB. Maxime Beaufort is gratefully acknowledged for performing part of the experiments during his internship at Jönköping University. Ansys is gratefully acknowledged for providing Granta Selector software through the Research Partnership with Tekniska Högskolan i Jönköping.

Conflicts of Interest

The authors declare no conflict of interest.

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