Int. J. Microstructure and Materials Properties, Vol. 12, Nos. 1/2, 2017 25
Copyright © 2017 Inderscience Enterprises Ltd.
A study on microhardness and microstructural
evolution of titanium/zirconium diboride cermet
coatings with varying scan speeds during laser
cladding on Ti6Al4V substrate
Gabriel Ayokunle Farotade*
and Abimbola Patricia Popoola
Faculty of Engineering and Built Environment,
Department of Chemical, Metallurgical
and Materials Engineering,
Tshwane University of Technology,
Pretoria, 0001, South Africa
Email: segunfarotade@yahoo.com
Email: PopoolaAPI@tut.ac.za
*Corresponding author
Abstract: Titanium/zirconium diboride cermet coatings were deposited at
different laser scan speeds on Ti–6Al–4V alloy using laser cladding technique.
Microhardness of the coatings was compared with the microhardness of the
substrate, while the microstructural morphologies of coatings were evaluated
via scanning electron microscope with energy dispersive spectroscopy. In
addition, resultant grain sizes of the coatings were observed and phases formed
within the coatings were also examined. The microhardness of the coatings was
seen to be four times harder than the substrate. Scanning electron microscopic
images exhibited a refinement in grain size and the development of distinct
microstructural features. X-ray diffraction patterns showed significant hard
phases such as Al
2
Zr and Ti
3
B
4
which may be responsible for the sky-rocketed
microhardness values of the coatings. This study proffers profound insight on
the influence of laser scan speed, during deposition, on the microhardness and
microstructural morphology of titanium/zirconium diboride cermet coatings.
Keywords: laser scan speed; titanium/zirconium diboride cermet coatings;
laser cladding technique; Ti6Al4V substrate.
Reference to this paper should be made as follows: Farotade, G.A. and
Popoola, A.P. (2017) ‘A study on microhardness and microstructural evolution
of titanium/zirconium diboride cermet coatings with varying scan speeds
during laser cladding on Ti6Al4V substrate’, Int. J. Microstructure and
Materials Properties, Vol. 12, Nos. 1/2, pp.25–37.
Biographical notes: Gabriel Ayokunle Farotade is currently a Doctoral
Research Assistant at the Department of Chemical, Metallurgical and Materials
Engineering, Tshwane University of Technology, Pretoria, South Africa. His
interest is in additive manufacturing, materials engineering and engineering
metallurgy. He has keen interest for research and development and has
produced few publications in the field.