High‐Performance Microwave‐Derived Multi‐Principal Element Alloy Coatings for Tribological Application

Abstract

The authors report the development of AlxCoCrFeNi (x = 0.1 to 3) high entropy alloy (HEA) coatings using a simple and straightforward microwave technique. The microstructure of the developed coatings is composed of a cellular structure and diffused interface with the substrate. The microstructure of the HEA coatings varies as a direct function of Al content. An increase in Al fraction shows structural transformation from FCC to BCC along with the evolution of σ and B2 as the major secondary phases. The diffusion of Mo from the substrate enhances the mixing entropy and promotes σ‐phase formation. The HEA coatings show significantly high hardness compared to SS316L substrate steel (227 HV) with a maximum value of 726 HV observed for three‐molar composition. The fracture toughness exhibits an inverse correlation with the Al fraction with the highest value of around 49 MPa m1/2 observed for Al0.1CoCrFeNi coating. The equimolar coating composition shows lowest erosion rates among all the tested samples due to optimum combination of the mechanical properties. The erosion resistance of the equimolar coating is 2 to 5 times higher than steel substrate and around 1.5 times higher than the non‐equimolar counterparts depending upon the impingement angles.

Slurry Erosion–Corrosion of Bimodal Complex Concentrated Alloy Composite Cladding

“…The detailed description of cladding's development has been provided elsewhere. [ 28 ] The feedstock powders were covered with the susceptor “charcoal” for uniform hybrid heating. The claddings were developed at an optimized time of 8 min and 900 W obtained after several trials.…”

Influence of Surface Treatments on Erosion Behavior of Various Steel Alloys- A Literature Review

“…Erosion rate was reduced considerably by applying such coatings for 30° impingement angle. At 90° impingement angle, erosion rate was comparatively very high [46]. slurry erosion behavior of Laser clad NiCoCrFeAl 3 high entropy alloy coating was studied and found significant improvement in slurry erosion resistance.…”

Complex Concentrated Alloys (CCAs)

“…The large amounts of the required data in Monte Carlo simulations usually increase the complexity of such simulations. It should be noted that some characteristics and properties of the MPE alloys have been studied by other numerical, analytical, and statistical analyses, such as lattice distortion by an analytical calculation method [80], lattice constants and short range order matrices by a theoretical atomistic model [81], densities and melting temperatures by a combination of physical and statistical models [82], and elemental diffusivities by combinations of different theoretical methods, including Darken and Miedema's scheme [83].…”

“…The figure displays the two main types of serrations: large primary serrations and small, interspersed secondary serrations. Serrations have also been observed in different phenomena, such as the Barkhausen noise in magnetic materials [8,[71][72][73][74] (see Figure 5), crackling noise during earthquakes [75][76][77][78], discrete strain bursts in nanocrystals [76], various economic indices [79][80][81][82][83], and neuronal avalanches that occur during the operation of the brain's network (see Figure 6) [84][85][86][87][88][89][90][91][92]. [92]).…”