O.B. Bembalge

Bio: O.B. Bembalge is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Ultimate tensile strength & Precipitation hardening. The author has an hindex of 7, co-authored 10 publications receiving 132 citations.

An environment-friendly and sustainable machining method: near-dry EDM

Abstract: Electric discharge machining (EDM) is one of the unconventional machining methods used in machining difficult-to-cut materials. The EDM process uses hydrocarbons-based dielectrics during ma...

High temperature oxidation study of direct laser deposited AlXCoCrFeNi (X=0.3,0.7) high entropy alloys

Abstract: High entropy alloys (HEAs) are being explored as prospective substitutes for high temperature structural components. These HEAs are typically fabricated using conventional techniques like arc melting, mechanical alloying etc., but these routes exhibit a wide range of limitations. Direct laser deposition (DLD) process (an additive manufacturing technique) generates complex products from metal powder by selectively melting alloy powder in successive layers. The present study shows the development of HEAs namely Al0.3CoCrFeNi, Al0.7CoCrFeNi possessing crystal structures face-centered cubic (FCC) and FCC plus body-centered cubic (BCC) respectively using direct laser deposition (DLD) technique. HEA plates of the above-mentioned alloys were fabricated using DLD technique. In the present work, microstructures, mechanical (mainly hardness) and cyclic oxidation behaviors at 1100 Cof developed HEAs have been investigated. Microstructural studies revealed FCC and FCC + BCC structures respectively, for Al0.3CoCrFeNi and Al0.7CoCrFeNi alloys with corresponding hardness of 170HV and 380HV. Cyclic oxidation studies were performed on the HEAs at a temperature of 1100 °C for 200 h. Both the HEAs displayed quasi parabolic oxide growth after an initial sharp growth slope. Over the studied oxidation period, the mass gain for HEA Al0.3CoCrFeNi was greater than for Al0.7CoCrFeNi. Each oxidized HEAs forms an external Cr2O3 scale with Al2O3 subscale formed beneath, but the thickness and continuity of oxide layers vary according to Al content. Increased Al content enhanced the oxidation resistance of the HEA.

Material-structure-performance integrated laser-metal additive manufacturing.

Abstract: BACKGROUND Metallic components are the cornerstone of modern industries such as aviation, aerospace, automobile manufacturing, and energy production. The stringent requirements for high-performance metallic components impede the optimization of materials selection and manufacturing. Laser-based additive manufacturing (AM) is a key strategic technology for technological innovation and industrial sustainability. As the number of applications increases, so do the scientific and technological challenges. Because laser AM has domain-by-domain (e.g., point-by-point, line-by-line, and layer-by-layer) localized forming characteristics, the requisite for printing process and performance control encompasses more than six orders of magnitude, from the microstructure (nanometer- to micrometer-scale) to macroscale structure and performance of components (millimeter- to meter-scale). The traditional route of laser-metal AM follows a typical “series mode” from design to build, resulting in a cumbersome trial-and-error methodology that creates challenges for obtaining high-performance goals. ADVANCES We propose a holistic concept of material-structure-performance integrated additive manufacturing (MSPI-AM) to cope with the extensive challenges of AM. We define MSPI-AM as a one-step AM production of an integral metallic component by integrating multimaterial layout and innovative structures, with an aim to proactively achieve the designed high performance and multifunctionality. Driven by the performance or function to be realized, the MSPI-AM methodology enables the design of multiple materials, new structures, and corresponding printing processes in parallel and emphasizes their mutual compatibility, providing a systematic solution to the existing challenges for laser-metal AM. MSPI-AM is defined by two methodological ideas: “the right materials printed in the right positions” and “unique structures printed for unique functions.” The increasingly creative methods for engineering both micro- and macrostructures within single printed components have led to the use of AM to produce more complicated structures with multimaterials. It is now feasible to design and print multimaterial components with spatially varying microstructures and properties (e.g., nanocomposites, in situ composites, and gradient materials), further enabling the integration of functional structures with electronics within the volume of a laser-printed monolithic part. These complicated structures (e.g., integral topology optimization structures, biomimetic structures learned from nature, and multiscale hierarchical lattice or cellular structures) have led to breakthroughs in both mechanical performance and physical/chemical functionality. Proactive realization of high performance and multifunctionality requires cross-scale coordination mechanisms (i.e., from the nano/microscale to the macroscale). OUTLOOK Our MSPI-AM continues to develop into a practical methodology that contributes to the high performance and multifunctionality goals of AM. Many opportunities exist to enhance MSPI-AM. MSPI-AM relies on a more digitized material and structure development and printing, which could be accomplished by considering different paradigms for AM materials discovery with the Materials Genome Initiative, standardization of formats for digitizing materials and structures to accelerate data aggregation, and a systematic printability database to enhance autonomous decision-making of printers. MSPI-oriented AM becomes more intelligent in processes and production, with the integration of intelligent detection, sensing and monitoring, big-data statistics and analytics, machine learning, and digital twins. MSPI-AM further calls for more hybrid approaches to yield the final high-performance/multifunctional achievements, with more versatile materials selection and more comprehensive integration of virtual manufacturing and real production to navigate more complex printing. We hope that MSPI-AM can become a key strategy for the sustainable development of AM technologies. Download high-res image Open in new tab Download Powerpoint Material-structure-performance integrated additive manufacturing (MSPI-AM). Versatile designed materials and innovative structures are simultaneously printed within an integral metallic component to yield high performance and multifunctionality, integrating in parallel the core elements of material, structure, process, and performance and a large number of related coupling elements and future potential elements to enhance the multifunctionality of printed components and the maturity and sustainability of laser AM technologies.

Recent Advances on High‐Entropy Alloys for 3D Printing

Abstract: Boosted by the success of high-entropy alloys (HEAs) manufactured by conventional processes in various applications, the development of HEAs for 3D printing has been advancing rapidly in recent years. 3D printing of HEAs gives rise to a great potential for manufacturing geometrically complex HEA products with desirable performances, thereby inspiring their increased appearance in industrial applications. Herein, a comprehensive review of the recent achievements of 3D printing of HEAs is provided, in the aspects of their powder development, printing processes, microstructures, properties, and potential applications. It begins with the introduction of the fundamentals of 3D printing and HEAs, as well as the unique properties of 3D-printed HEA products. The processes for the development of HEA powders, including atomization and mechanical alloying, and the powder properties, are then presented. Thereafter, typical processes for printing HEA products from powders, namely, directed energy deposition, selective laser melting, and electron beam melting, are discussed with regard to the phases, crystal features, mechanical properties, functionalities, and potential applications of these products (particularly in the aerospace, energy, molding, and tooling industries). Finally, perspectives are outlined to provide guidance for future research.

Recent research and development status of laser cladding: A review

Abstract: In industries such as aerospace, petrochemistry and automobile, many parts of different machines are under environment which shows high temperature and high pressure, and have their proneness to wear and corrosion. Therefore, the wear resistibility and stability under high temperature need to be further improved. Nowadays, Laser cladding (LC) is widely used in machine parts repairing and functional coating due to its advantages such as lower dilution rate, small heat-affected zone and good metallurgical bonding between coating and substrate. In this paper, LC is introduced in detail from aspects of process simulation, monitoring and parameter optimization. At the same time, the paper gives a comprehensive review over LC material system as high entropy alloys (HEAs), amorphous alloy and single crystal alloy have been gradually showing their advantages over traditional metal materials in LC. In addition, the applications of LC in functional coatings and in maintenance of machine parts are also outlined. Also, the existing problems and the development trend of LC is discussed then.