High entropy alloys (HEAs) are being attracted recently by several researchers, scientists, and academicians to achieve extraordinary and outstanding properties that cannot be obtained from conventional alloys. HEAs are multicomponent alloys in which a minimum of five metallic elements are mixed in an equal molar or non-equal molar ratio. The rapid growth of this field produces a huge amount of scientific papers over the last decade. However, still, there is a need to review various manufacturing methods and their results. Also, the outcome of the scientific articles related to HEAs has ignored the various methods of synthesizing and manufacturing. In this review article, an attempt was made and largely concentrated on the methods and techniques that can be used in the manufacturing and synthesizing of the HEAs. Recently, the properties of HEAs become much better when compared to conventional alloys. Some techniques have succeeded in producing ultrafine microstructure grains which become a leap in industrial fields. Now, the manufacturing methods of conventional alloys are almost familiar and implemented according to the suggestions given by the researchers and academicians based on their work. Therefore, the present review article has demonstrated various methods of manufacturing of HEAs with novel schematics with a preview description for more understanding of the basic work criteria. Besides, this article has reviewed the outcomes of several research articles related to several methods, then compared the outcome of each method with the corresponding mechanical properties, and major challenges of HEAs are discussed and reported.

This paper presents the results of an experimental investigation carried out to control the base pressure in a suddenly expanded axi-symmetric passage. Active control in the form of micro jets was employed to control the base pressure. Air injection at four locations at the base, symmetric to the nozzle axis was used as the active control. The jet Mach numbers at the entry to the suddenly expanded duct studied were 1.87, 2.2 and 2.58. The area ratio of the present study was 2.56. The length-to-diameter ratio of the suddenly expanded duct varied from 10 to 1. Nozzles generating the above jet Mach numbers were operated with nozzle pressure ratio (NPR) in the range 3 to 11. In addition to base pressure, wall pressure field along the duct was also studied. It is found that the active control in the form of blowing through small orifices (micro jets) are effective in controlling the base pressure field. As high as 65 percent increase in base pressure was achieved for certain combination of parameters of the present study. Micro jets do not disturb the flow field in the enlarged duct.

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Additive manufacturing technology can help us to produce complex components/parts easily. It can be used to develop the parts with multi-material structures consisting of thermoplastic, thermosetting plastic, and ceramic fibers. This multi-material structure enhances the performance of lightweight polymer-based components. In this research work, poly-lactic acid (PLA) lattice (mono-material structure), PLA lattice filled with epoxy (bi-material structure), and PLA lattice incorporated with embedded milled glass fibers (MGFs) in an epoxy matrix (tri-material structure, TMS) were designed and developed by fused filament fabrication and solution casting methods. PLA lattice of 50% volume was fixed in all structures and 50% volume was filled with epoxy and MGFs. The dispersed MGFs in epoxy matrix were varied from 0, 2.5, 5, and 7.5 vol%. The mechanical properties were carried out by compression test, three-point bending test, and tensile test. The results revealed that 5 vol% of MGFs in the epoxy sample (TMS) exhibited improved mechanical performances compared to other samples. The cone-beam CT scan results confirmed the voids/porous free surfaces in the developed materials. The high-resolution scanning electron microscope microstructural evolutions in-terms of topography and fractured regions were also examined and reported.