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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 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.

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.

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.

International audience; Towns are characterized by a strong intern dynamic, a very high spatial heterogeneity of their elements, their 3D geometric shapes (horizontal and vertical) inducing shadows, and their large variety of materials. These characteristics make the collection of information of land surface properties and urban descriptors more delicate. Due to the enhancement of spatial resolution capacities,[virgule] multispectral imagery can provide a wide range of information to deepen the observation of urban areas. Nevertheless, such a type of sensors would not contribute to the characterization of the urban land surface properties (chemical composition of materials, species of vegetation, quality of soils, etc.). Hyperspectral imagery capacities might be considered as providing useful products by themselves and show great potentials but it becomes mandatory to define which type of information can be delivered by these different sensors. The ANR HYEP project 1 has the purpose to demonstrate the benefit of a second generation of hyperspectral space borne mission characterized by a high spatial resolution (8m GSD) and a high temporal revisit. After a detailed description of the motivation of such a proposal, applications are given focused on urban vegetation, sealed and impervious areas, solar panel area estimation.