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Powder Bed Fusion (PBF) is an Additive Manufacturing (AM) process. It is the layer by layer addition process. In the future, it is going to be manufactured all types of products used in automotive, aerospace, energy sectors and home appliances. These products can be produced using various AM methods. Few of them are Laminated Object Manufacturing, Powder Bed Fusion and Direct Energy Deposition, Stereolithography (SLA), and Solid Ground Curing (SGC). The present brief review is concentrated on working of PBF process only. It includes Direct Metal Laser Deposition (DMLS), Selective Laser Sintering (SLS), Selective Laser Melting (SLM), Electron Beam Melting (EBM) and Selective Heat Sintering (SHS). In these processes powder lay on the powder bed and it is also known as built platform. Laser used as heat energy source for SLS, SLM and DMLS processes. But EBM uses electron beam as source of energy. The SHS process uses heated thermal head for sintering plastic powders. SLS, DMLS and SHS are powder sintering processes. But SLM and EBM are powder melting processes. This review paper is also covered historical development and usage of technologies, CNC verses Additive Manufacturing/Rapid Prototyping, AM process chain, Classification of AM processes; advantages, disadvantages and applications of PBF process.

The present study aims at assessing the mechanical behavior of aluminum alloy (AA2024) subjected to exfoliation corrosion. The material was exposed to high temperature and subsequent low temperature (HLA) treatment and further the heat-treated samples were subjected to exfoliation corrosion for the duration of 48 and 96 h at room temperature. The HLA treatment increases the retention property of material in the corrosive environment. Further, hardness and impact strength was also increased under the corrosive environment with HLA treatment. In addition to the experimental investigation, a series of simple second-degree polynomial equations were developed to predict the various mechanical properties at different intervals of corrosion durations of AA2024 specimens subjected to HLA exfoliation corrosion.

The effect of machining parameters on the thrust force, torque and burr height while drilling Al 2618, Al2618 with 10% boron carbide (B4C) and Al2618 with 10%B4C and 5% graphite (Gr) hybrid composites are addressed. The composites are produced using a process of liquid metallurgy. The findings indicate that, feed rate had a significant impact on thrust force and the height of the exit burr. The Al2618 + 10% B4C-5%Gr reinforced hybrid composites exhibit smaller thrust force and burr height in contrast to the Al2618 + 10% B4C composite. The reduced thrust force, torque and burr height was due to the strong graphite surface lubrication properties. The chips produced while machining graphitic composites are discontinuous, and hence beneficial.

The present investigation was focused to evaluate the mechanical properties of AA7075 subjected to corrosion and heat treatment. Exfoliation corrosion has been used to infuse rapid corrosion on the material coupled with high temperature and subsequent low-temperature aging (HLA). It has been found that the localized corrosion pit formation occurs with HLA and corrosion exposure durations with substantial inter-granular changes and the formation of cracks. A significant reduction in mechanical properties was observed with HLA-treated samples subjected to corrosion. The material’s stiffness was increased due to HLA, and again within the corrosive environment, a decreasing trend was observed with immersion durations. A series of simple one-dimensional linear and polynomial equations were developed to determine the properties of AA7075 samples subjected to HLA and corrosion.

The heat transfer is assumed to take place in a porous medium under the influence of two sources such as a whole surface applied with hot temperature and another small strip of heating element being kept at left side of the cavity. The governing equations are derived from the basic principle of Darcy flow. The impact of the heating strip length is investigated with respect to its position at x = 0.25L of the cavity with L being the length of cavity. Finite element method is used to form a set of equations in algebraic form that can be solved easily with the help of a computer code. The solution is set with proper tolerance limit to get accurate results. The results indicate that the position of element has impact on the heat transfer from hot to cold surface.

This article is aimed to study the thermal energy transport phenomenon caused by heating the porous cavity at left vertical wall as well as an internal heating by a strip of varying length near the cooling surface. The internal heating strip that varies in length is kept at x = 3L/4 of the cavity where L is the overall cavity length. Finite element method is at the core of solution techniques which is employed along with triangular shaped elements. The solution is arrived by following an iterative method that depends on satisfying the equations to a predetermined error level. It is ensured that the results are accurate enough to predict the phenomenon under study. The main aim of the study is to understand what happens when the heating element is placed towards the right vertical surface. The results are described for physical and geometrical parameters of the problem being considered.

Current study deals with the microstructural characterization of five different plates of steel with carbon concentration ranging from ultra-low to moderately high. Phase analysis was carried out using XRD technique. The XRD results were analyzed through Rietveld refinement and Williamson Hall plots. Rietveld refinement was carried out to understand the effect of carbon concentration on the lattice parameters of the above steel samples in as-received condition and also after deformation under uni-axial tensile loading. Lattice parameters obtained from refinement showed the strong dependence on carbon concentration of the given steels. But the failed specimens showed somewhat complex results as Spheroidized high carbon steel, Low carbon steel and IF steel showed an increase in lattice parameter whereas Medium carbon steel and Microalloyed steel showed a contraction in lattice parameter. Williamson Hall plot gave the crystallite size, microstrain and dislocation density in the steels. For IF and Microalloyed steels the dislocation density in the material is found to be higher after deformation whereas dislocation density decreased in Spheroidized high carbon steel, Medium carbon steel and Low carbon steel.

This article deliberates the finite element formulation as applied to the conjugate heat transfer in a porous domain fixed in an annular geometry. The porous domain is such that a solid wall is attached to the iner surface of annulus. The article is aimed to discuss the application of finite element method to problem under investigation and elaborate the solution strategy as applied to porous annulus. The governing equations are taken in the form of non-dimensional equations. A simple triangular element is used to simulate the problem under investigation. The solution is presented in terms of convergence behavior of temperature and stream function. The convergence is faster at low Rayleigh numberThis article deliberates the finite element formulation as applied to the conjugate heat transfer in a porous domain fixed in an annular geometry. The porous domain is such that a solid wall is attached to the iner surface of annulus. The article is aimed to discuss the application of finite element method to problem under investigation and elaborate the solution strategy as applied to porous annulus. The governing equations are taken in the form of non-dimensional equations. A simple triangular element is used to simulate the problem under investigation. The solution is presented in terms of convergence behavior of temperature and stream function. The convergence is faster at low Rayleigh number

The tribological behavior of the different structural steels with carbon concentration ranging from 0.002 to 0.7% was evaluated through ball on disk wear testing method. Testing was carried out at three different loads, i.e., 30, 40, and 50 N to understand the wear behavior at different loading conditions. The wear resistance of the spheroidized high carbon steel (0.7%) is found to be lesser than that of steels containing pearlite in their microstructures, i.e., low carbon (0.19%) steel and medium carbon (0.32%) steel. Enhanced strain hardening of the pearlite structure was held responsible for the increased wear resistance. As expected if steel showed least wear resistance due to its softer ferrite content. The SEM images of the worn structures are correlated with the macroscopic wear resistance data.

Recycling has been the fascinating topic among the researchers for all times. The present study shows the recycling of steel plant's solid wastes as blast furnace flue dust and sludge towards agglomeration and their use in the production of sinter. These wastes consist of metal oxides and coke fines as a valuable material with some alkali oxides. Using these wastes as it is in the form of fines exacerbate the further processing. Pellets of these wastes are prepared with three types of binders as molasses, dextrin and bentonite. The result reveals that properties as compressive strength, shatter strength, are better in the case of bentonite binder having the productivity of the disc pelletizer machine as 75. After that, these macro pellets used for sintering with iron ore and other ingredients in pot type, down draft laboratory grade sintering machine, which shows very high productivity and good mechanical properties of the sinter as well. The microstructural analysis reveals the presence of re-oxidized hematite and a little bit of a magnetite phase with some slag phases, which confirmed later by XRD analysis. Results also show the decrease in coke rate, i.e. coke consumption to produce sinter and at the same time, this process is highly eco-friendly.

Opposing flow arises when two forces are acting in opposite direction. The present work investigates the opposing flow mixed convection in an annulus having porous medium fixed within its boundaries. The equations are considered in non-dimensional form which is further treated with the help of finite element method to facilitate the solution of governing parameters. The heating of the inner surface is considered in 3 steps such as 20%, 35% and 50% of the annulus height at top section of inner radius. The results are presented with respect to Peclet number, thermal conductivity ratio and heater length, in terms of Nusselt number along the heated section.Opposing flow arises when two forces are acting in opposite direction. The present work investigates the opposing flow mixed convection in an annulus having porous medium fixed within its boundaries. The equations are considered in non-dimensional form which is further treated with the help of finite element method to facilitate the solution of governing parameters. The heating of the inner surface is considered in 3 steps such as 20%, 35% and 50% of the annulus height at top section of inner radius. The results are presented with respect to Peclet number, thermal conductivity ratio and heater length, in terms of Nusselt number along the heated section.

Opposing flow mixed convection occurs due to the fluid being forced to flow in opposing direction as that of rising fluid due to thermal buoyancy. This paper undertakes the investigation of heat transfer in an annular porous medium because of mixed convection opposing flow from top of the cylinder. The fluid velocity designated as Vo is applied from top of the cylinder in negative gravitational direction. The governing equations are converted into dimensional form having the Peclet number. The inner radius of the annulus is heated in three segments as 20%, 35% and 50% of the annulus height in such a way that the heater always coincides with the bottom of cylinder.Opposing flow mixed convection occurs due to the fluid being forced to flow in opposing direction as that of rising fluid due to thermal buoyancy. This paper undertakes the investigation of heat transfer in an annular porous medium because of mixed convection opposing flow from top of the cylinder. The fluid velocity designated as Vo is applied from top of the cylinder in negative gravitational direction. The governing equations are converted into dimensional form having the Peclet number. The inner radius of the annulus is heated in three segments as 20%, 35% and 50% of the annulus height in such a way that the heater always coincides with the bottom of cylinder.

This paper discusses the heat transfer characteristics of mixed convection in a porous medium for aiding flow. The aiding flow refers to a condition when the applied velocity and the buoyancy help each other making it a assisting flow. The annulus is subjected to discrete heating of 20%, 35% and 50% at bottom of the annulus being heated with hot temperature and whole of the outer surface being cooled to cooler temperature. The whole phenomenon of mixed convection is simulated with respect to above said heating condition by using finite element method as solution tool. The results are predominantly discussed with respect to the mixed convection parameter such as Peclet number.This paper discusses the heat transfer characteristics of mixed convection in a porous medium for aiding flow. The aiding flow refers to a condition when the applied velocity and the buoyancy help each other making it a assisting flow. The annulus is subjected to discrete heating of 20%, 35% and 50% at bottom of the annulus being heated with hot temperature and whole of the outer surface being cooled to cooler temperature. The whole phenomenon of mixed convection is simulated with respect to above said heating condition by using finite element method as solution tool. The results are predominantly discussed with respect to the mixed convection parameter such as Peclet number.

Base pressure is a crucial factor in evaluating flow parameters. The effect of the flow regulation mechanism is through an experiment examined for the convergent-divergent (C-D) nozzle with abrupt enlargement in an axisymmetric duct. The microjet control is extended along the nozzle's exit diameter at a 90-degree interval having a circular cross-section in the shape of an orifice of 0.5 mm radius. This research's primary aim is to evaluate the flow quality near the wall in the absence and presence of control. The experimental investigation aims to record the data for area ratio 6.25 of the flow field at the separate flow zone's rear end. At ninety degrees apart, four tiny jets are situated at 6.5 mm from the axis of the primary shear layer emanating from the nozzle. The small control jets attain critical conditions. The real Mach values for the main jets were 1.1 and 1.5, respectively, in the present study. The experiments were done at different expansions in the range from 11 to 3. The duct length was in the range of 10 to 1. This research primarily aims to study the quality of the duct's flow and its influence on the pressure and the pressure level along the duct. It is realized that the duct pressure is not harshly affected by the control jets in the pipe founded on the current findings.

The strain hardening behavior of five different steels of varying carbon content, ranging between 0.007 and 0.71%, such as an Interstitial free (IF), a microalloyed, and a low, medium and high carbon steels, have been critically examined using tensile loading. The test results for the IF and the microalloyed steels having only ferritic structure, exhibit a two-stage strain hardening behavior. On the other hand, the low, medium, and high carbon steels having a two-phase microstructure (ferrite-pearlite/cementite) exhibit three-stage strain hardening. A number of existing and frequently used empirical equations, such as the Hollomon, Ludwik, Ludwigson and Voce were used to explain the strain-hardening characteristics of these steels; however, none of the above could fully and satisfactorily explain the flow behavior especially at high strain region. In order to remedy this deficiency, a modification to Ludwigson equation has been suggested by the authors by introducing an extra exponential term to the existing Ludwigson equation. The modelled flow curves, on the basis of this proposed new equation, could explain the strain hardening behavior of these steels very satisfactorily over the entire strain range. In addition, the excellent matching of the flow curves, based on the proposed equation with the experimental flow curves of a number of metallic materials, as diverse as multiphase steel, TRIP-assisted steel, dual-phase steel, stainless steel (316L), Mg-alloy, Ti-alloy and a high entropy (Cantor) alloy, indicates its wider applicability.

Our previous article (Part I) discussed the theoretical and experimental study of the performance boost obtained by a cooking vessel with central cylindrical cavity on lugs when compared to that of a conventional cylindrical vessel on floor/lugs. This article compares the performance of the cooking vessel with depressed lid on lugs with that of the conventional vessel on lugs. A mathematical model is presented to understand the heat flow process to the cooking vessel and, thereby, to the food material. It is found from the experiments that the cooking vessel with depressed lid results in higher temperature of the thermic fluid loaded in the cooking vessel compared to that of the thermic fluid kept in the conventional vessel when both are placed on lugs. Similar results were obtained by modeling the process mathematically. The average improvement of performance of the vessel with depressed lid is found to be 8.4% better than the conventional cylindrical vessel.

In this paper an attempt has been made to investigate the resistance characteristics of high-speed round bilge hull forms fitted with a vane in the stern region of the vessel. The Hull Vane ® is a fixed foil located below the waterline, aft of the stern of the vessel. The Hull Vane® reduces the generation of waves and the vessel’s motions in waves. The focus of this paper is to compare the total resistance of a single model from the AMECRC series of round bilge hull forms with and without Hull Vane® attached to the hull.