Mon, 30 September, 2024
A new paper, co-written by staff at TWI and published in the Journal of Thermal Spray Technology, is now available to read online.
The study, ‘Optimizing Cold Spray Parameters for High Entropy Alloy Coatings Using Taguchi and Box–Behnken Design Approaches for Mechanically Alloyed Powder,’ was co-written by TWI’s Deepak Sharma, Dibakor Boruah, Ahamed Ameen, Ali Alperen Bakir and Shiladitya Paul.
It focused on the optimisation of cold spray process parameters for depositing Fe20Cr20Mn20Ni20Co20 (Cantor alloy) coatings using mechanically alloyed powder. Two sets of experiments were undertaken, firstly, an initial screening of input variables using the L8 Taguchi method, before the process parameters were refined via Box–Behnken experiments.
Key performance indicators for the tests included deposition efficiency and coating thickness per pass, as well as microstructural parameters including porosity, cracks, and interfacial defects/delamination.
The paper confirms that process gas temperature was the primary factor influencing deposition efficiency and thickness per pass, with a higher gas temperature and pressure, combined with increased scanning speed, resulting in higher deposition efficiencies.
The deposition efficiency of the mechanically alloyed Cantor alloy powder peaked at around 14-15%, with a deposit density greater than 99% achieved at the highest process gas temperature and pressure (1000 °C and 60 bar, respectively).
The average hardness of the optimal CS coating deposited using mechanically alloyed powder was found to be 679 ± 17 HV0.1, which is approximately 90% greater than the average hardness reported for cold spray coatings deposited using atomised powder.
You can find out more by reading the paper in full, here.