Nanocomposites and nanomaterials

Mechanical properties of nanostructured AlNiCoFeCrTi 
high-entropy coating performed by cold spray
Yurkova A.I., Hushchyk D.V., Chernyavsky V.V., Nakonechnyy S.O. 

High-Temperature Materials and Powder MetallurgyDepartment, Igor Sikorsky Kyiv Polytechnic Institute,
Prospect Peremogy, 37, Kyiv-03056, Ukraine. 
E-mail: d.hushchyk@gmail.com 

In this work, the complex of mechanical characteristics, such as microhardness, HV, Young’s modulus, E, yield stress, y, and fracture toughness, K1C, of nanostructured AlNiCoFeCrTi high entropy coatings [1], obtained by cold spray (CS), was determined by indentation technique. Mechanical parameters were obtained in cross-section of CS coatings.
Microhardness measurements were performed using a conventional microhardness machine equipped by standard Vickers’ pyramid. Microhardness numbers were determined under indentation loads not higher than 1.5 N. Yield stress, y, was extracted from ‘stress-strain’ curves constructed by a set of trihedral pyramids with different angles at the tip 1 (ranged from 45 to 85) according to the test method procedure [2]. The indentation fracture toughness (IFT) was determined using the Vickers hardness indentation method [3]. Microtester capable for load-displacement measurements and equipped by Berkovich pyramid was used to determine Young’s modulus, E, which was determined from complete cycle of loading and unloading data and computed according to the test method procedure originally proposed by of Oliver and Pharr [4].
The experimental results confirm that CS can be used to produce HE coatings with high mechanical characteristics. 

1.	Hushchyk D.V., Yurkova A.I., Chernyavsky V.V., and et. al. Nanostructured  AlNiCoFeCrTi high-entropy coating performed by Cold Spray // International conference NANO-2019 27-30.09.19, Lviv, Ukraine. -P. 84.
2.	Galanov, B.A., Milman Yu.V., Chugunova S.I., Goncharova I.V. Investigation of mechanical properties of high–hardness materials by indentation // J. Superhard Mater.-1999.-21.-P. 23-35.
3.	Anstis G.R., Chantikul P, Lawn B.R., Marshall D.B. A critical evaluation of indentation techniques for measuring fracture toughness: I, direct crack measurements // J Am. Ceram. Soc.-1981.-64(9).-P. 533-538
4.	Oliver W.C., Pharr G.M. An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments // J. Mater. Res.-1992.-7.-P. 1564-1583.