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RRJOMS | Volume 5 | Issue 4 | July, 2017
July 27-29, 2017 Vancouver, Canada
10th International Conference on
Emerging Materials and Nanotechnology
Microstructure and surface properties of Ti-6Al-4V cold spray coated with SiC-based cermet
Isaac D Adebiyi
Vaal University of Technology, South Africa
Statement of the Problem: A more ubiquitous application of Ti-6Al-4V in the aerospace industry has been hindered by its
poor set of surface properties. The cold spray coating (CSC) process is suitable for improvements in the surface properties but
the process is very complex, and highly dependent and sensitive to small changes in its many process parameters. Moreover,
the CSC is also very selective of the choice of powder materials. The choice is not only based on application requirements but
also on plastic deformability of the powder.
Methodology & Theoretical Orientation: This investigation presents a mathematical identification of the optimum process
parameters by using a constitutive equation to solve the continuity, momentum and the energy equations governing the flow
of fluid through the low-pressure cold spray nozzle. A CFD analysis is performed to determine the input temperature that
will yield the calculated velocity by using the meshing tool of solid works to analyse the distribution of velocity, temperature,
and pressure in the cold spray nozzle and predict their exit values. The optimum parameters were used to deposit a SiC-based
cermet on Ti-6Al-4V. The microstructure and phase evolution in the coatings were studied; porosity was measured using
ImageJ analysis software; the hardness was measured using Vickers hardness tester; adhesion test was performed according
to ASTM C633-1; and the dry sliding wear behaviour was studied in a ball-on-disc configuration using a load of 25 N at a
frequency of 5 Hz.
Findings: Results showed that the initial phases in the feedstock powder were retained in the coatings. No detrimental phase
transformation, decomposition and/or decarburization of the SiC. There was peak shift between the phases in the feedstock
powder that of the coatings. This is traced to impact-induced micro-straining, amorphization and grain refinement. Good
adhesion strength and improvements in hardness and wear resistance were obtained in the coated samples although with a
higher coefficient of friction which is traceable to higher strength and lack of micro films in the coating.
Conclusion & Significance: The improved surface properties of the coating will lengthen the lifespan of the expensive Ti-6Al-
4V alloy, leading to significant cost savings for the aerospace industry.
Biography
Isaac DAdebiyi D is a Lecturer in the Department of Metallurgical Engineering, Vaal University of Technology, Vandebijlpark, SouthAfrica. He holds a Doctoral degree
in Metallurgical Engineering with specialization in new materials development. His research interests include surface modification of engineering materials (Laser
Materials Processing, Cold Spray Coating, High Velocity Oxy Fuel Coating, etc.), additive manufacturing, computational fluid dynamics modelling and simulation,
tribology and wear mitigation, process optimization, alloy design and physical metallurgy of alloys, microstructure and phase evolution studies, multifunctional
coatings development, and development of smart and advanced materials. He received an award for Innovation and Excellence in the use of stainless-steel by
the Southern Africa Stainless-steel Development Association. He has authored many publications and has chaired plenary section and moderated international
conference.
Isaac D Adebiyi, Res. Rev. J Mat. Sci. 2017
DOI: 10.4172/2321-6212-C1-002