Title: Enhanced tribological properties of aluminium using laser-assisted tungsten coating

Authors: Anurag Roy; Akshat Sharma; Aman Gupta; Vijay Meena; A.P. Harsha

Addresses: Indian Institute of Technology (BHU), Varanasi, 221005, India ' Purdue University, West Lafayette, Indiana 47907, USA ' Indian Institute of Technology (BHU), Varanasi, 221005, India ' Indian Institute of Technology (BHU), Varanasi, 221005, India ' Indian Institute of Technology (BHU), Varanasi, 221005, India

Abstract: Aluminium (Al) suffers from poor wear and scratch resistance and also low surface hardness. To overcome this, the authors fabricated a ~200 µm coating of fine tungsten (W) powder on Al using laser surface alloying (LSA) with laser power and scanning speed varying from 400-800 W and 800-1,200 mm/min respectively. Material characterisation in the form of SEM and XRD, undertaken on the LSA samples, revealed novel microstructures including formation of intermetallic phases Al₄W, Al₁₂W that exhibit substantially higher hardness. Scratch hardness measurements further consolidated that surface hardness of coated samples was more than three times as compared to bulk aluminium. Scratch testing at normal loads of 50-150 N, scratch speed of 30 mm/min, demonstrated a stable friction coefficient of 0.6 and higher coating adhesive strength. When applied to automobile components and aerospace products, the micro-coated LSA samples can provide far better alternatives to the current industrial grade of aluminium from the tribology point of view.

Keywords: laser surface alloying; LSA; wear resistance; scratch hardness; scanning electron microscopy; SEM; X-ray diffraction; XRD; intermetallics; micro-coatings; material characterisation.

DOI: 10.1504/WRSTSD.2018.093215

World Review of Science, Technology and Sustainable Development, 2018 Vol.14 No.2/3, pp.102 - 118

Received: 03 Jul 2017
Accepted: 05 Nov 2017
Published online: 14 Jul 2018 *

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