We investigated the structure–property correlation for the complex concentrated alloy (CCA) coatings prepared using different precursor powders. Al3CoCrFeNi CCA precursor powders were prepared through mechanical alloying (MA) (ball milling) and direct mixing (DM). CCA coatings were developed using microwave technique through hybrid heating approach. Coatings showed good metallurgical bonding with substrate exhibiting cellular growth structure. Microstructure for both coatings was primarily composed of A2 phase segregated with B2 phase at intercellular region. CCA coatings with different precursors showed insignificant influence on hardness, elastic modulus and cavitation erosion. Nonetheless, coating developed with MA precursor showed slightly lower fracture toughness compared to DM, mainly attributed to inherently higher fraction of intermetallic B2 phase. We showed that direct mixing is an efficient and effective route for developing CCA coatings. © 2018 Elsevier B.V.

Harpreet Singh Grewal

Mechanical Engineering

(SoE) School of Engineering

Nair R.B.

Arora H.S.

Mandal P.

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Shiv Nadar University

Materials Letters

<p>Hydro machinery components such as turbines, pipes, guide vanes, and pumps suffer from severe slurry erosion caused by the abrasive particles entrained in working fluid. In the current work, an array of systematic slurry erosion tests were executed to study the influence of impact angle on slurry erosion rates of Ni-SiC based composite claddings developed on SS 316&nbsp;L through microwave hybrid heating. Various microstructural and mechanical characterizations such as micro and nano-indentation, x-ray diffraction (XRD), and scanning electron microscopy (SEM) were performed on the developed claddings. The claddings contain 5&nbsp;wt.\% of SiC particles of different size fractions from nano to micro (unimodal) and combination of both in the matrix (bimodal). Slurry erosion studies were performed on the developed claddings at different impingement angles. The claddings exhibited good metallurgical bonding with the substrate without any pores throughout. The developed claddings exhibited high hardness and elastic modulus compared to the substrate material. A significant improvement in the erosion resistance of the claddings was observed with the addition of bimodal sized SiC secondary particles. The enhanced erosion resistance of the claddings could be attributed to the higher fracture toughness and hardness of the developed coating. Among the developed coatings, the bimodal sample with 5\% SiC claddings showed at least two times better erosion resistance than hydro-turbine steel at almost all the impact angles. SEM studies performed on the eroded samples showed micro-cutting and plowing as the main modes of material removal at lower impact angles. © 2021, Springer Nature B.V.</p>

Silicon

Slurry Erosion Resistance of Microwave Derived Ni-SiC Composite Claddings

Cavitation erosion and corrosion of structural materials are serious concerns for marine and offshore industries. Durability and performance of marine components are severely impaired due to degradation from erosion and corrosion. Utilization of advanced structural materials can play a vital role in limiting such degradation. High entropy alloys (HEAs) are a relatively new class of advanced structural materials with exceptional properties. In the present work, we report on the cavitation erosion behavior of Al0.1CoCrFeNi HEA in two different media: distilled water with and without 3.5 wt\% NaCl. For comparison, conventionally used stainless steel SS316L was also evaluated in identical test conditions. Despite lower hardness and yield strength, the HEA showed significantly longer incubation period and lower erosion-corrosion rate (nearly 1/4th) compared to SS316L steel. Enhanced erosion resistance of HEA was attributed to its high work-hardening behavior and stable passivation film on the surface. The Al0.1CoCrFeNi HEA showed lower corrosion current density, high pitting resistance and protection potential compared to SS316L steel. Further, HEA showed no evidence of intergranular corrosion likely due to the absence of secondary precipitates. Although, the degradation mechanisms (formation of pits and fatigue cracks) were similar for both the materials, the damage severity was found to be much higher for SS316L steel compared to HEA. © 2017 Elsevier B.V.

Fulltext

Ultrasonics Sonochemistry

Exceptionally high cavitation erosion and corrosion resistance of a high entropy alloy

Thin Solid Films

Nanocrystalline high-entropy alloy (CoCrFeNiAl0.3) thin-film coating by magnetron sputtering

Composites Part A: Applied Science and Manufacturing

Microwave–material interaction phenomena: Heating mechanisms, challenges and opportunities in material processing

Microwave assisted synthesis of Si-modified Mn25FexNi25Cu(50−x) high entropy alloys

Laser additive synthesis of high entropy alloy coating on aluminum: Corrosion behavior

Complex concentrated coatings: Effect of processing route on microstructural and mechanical properties