Effect of brass interlayer on microstructure, mechanical and corrosion behaviour of friction stir welded AA6061-T6 alloy

In this study, friction stir welding (FSW) was performed on AA6061-T6 with and without brass interlayer. The FSW with interlayer was performed for various tool rotational speeds (600–1000 r/min) and at constant travel speed (25 mm/min). The defect-free joint with uniform distribution of brass particles in the stir zone (SZ) and formation of the uniform composite structure was observed at an intermediate optimized tool rotational speed of 800 r/min due to the proper material flow. A strong metallurgical bond between brass particles with aluminium alloy resulted in the formation of Al2Cu and Al4Cu9 strengthening intermetallic compounds (IMCs). The average grain size obtained for the weld with interlayer is smaller than weld without interlayer. The presence of the interlayer enhanced the hardness and the tensile strength compared to the weld without interlayer. This improvement in mechanical properties with interlayer is attributed to the formation and uniform distribution of strengthening IMCs. The corrosion analysis was carried out in 3.5% NaCl solution using immersion test and electrochemical polarization test. The weld with interlayer showed enhanced corrosion resistance than the weld without interlayer which is attributed to the formation of major Al2Cu IMC which has less activation energy for the corrosion process.

Crack behaviour at the interface of a surface layer applied on a steel substrate by laser cladding

An influence of the bi-material interface between a steel substrate and a thin protective layer applied through laser cladding was investigated. A range of elastic properties and thicknesses of the layer were considered to cover the behaviour of a short crack in the selected materials such as bronze, nickel or cobalt alloys. The special case of the crack terminating directly at the interface was investigated, which is connected to the necessity of application of generalized approaches of linear elastic fracture mechanics. The results contribute to better understanding of fracture response of selected materials and to a more reliable decision on choosing a proper material of the protective layer.

A compact platform for the investigation of material dynamics in quasi-isentropic compression to ~ 19 GPa

This paper reports on the development of a magnetically driven high-velocity implosion experiment conducted on the CQ-3 facility, a compact pulsed power generator with a load current of 2.1 MA. The current generates a high Lorentz force between inner and outer liners made from 2024 aluminum. Equally positioned photonic Doppler velocimetry probes record the liner velocities. In experiment CQ3-Shot137, the inner liner imploded with a radial converging velocity of 6.57 km/s while the outer liner expanded at a much lower velocity. One-dimensional magneto-hydrodynamics simulation with proper material models provided curves of velocity versus time that agree well with the experimental measurements. Simulation then shows that the inner liner underwent a shock-less compression to approximately 19 GPa and reached an off-Hugoniot high-pressure state. According to the scaling law that the maximum loading pressure is proportional to the square of the load current amplitude, the results demonstrate that such a compact capacitor bank as CQ-3 has the potential to generate pressure as high as 100 GPa within the inner liner in such an implosion experiment. It is emphasized that the technique described in this paper can be easily replicated at low cost.

Investments in higher education during distance learning

Финансирование высшего образования в России осуществляется из государственных и негосударственных источников. Государственное финансирование образования традиционно является доминирующим, однако его размеры недостаточны для надлежащего материально технического обеспечения учебного процесса и научно-технической деятельности. Проблема финансирования высших учебных заведений в России особенно обострилась вследствие финансово-экономического кризиса. С одной стороны, сократились возможности бюджетного финансирования ВУЗОВ и, как следствие, уменьшился уровень заработной платы профессорско-преподавательского состава, снизились расходы бюджета на научные исследования, приостановления бюджетного финансирования льготных кредитов на строительство жилья для научно педагогического и педагогического персонала; с другой стороны – относительно возросла доля средств специального фонда, заработанных собственно государственными высшими учебными заведениями. На данный момент большинство механизмов финансирования высшего образования, доказавших свою эффективность в развитых странах, все еще недостаточно распространены в России или недостаточно активно используются высшими учебными заведениями. В частности, практически не используется потенциал грантового финансирования, государственно-частного партнерства и тому подобное. Ученые называют практическое отсутствие в стране практики государственного стимулирования участия корпоративного сектора в финансировании высшего образования «структурными перекосами», хотя мировой опыт свидетельствует об осознании на микроуровне важности компетенции работников, что стимулирует инвестирование работодателями в повышении их образовательного уровня. Financing of higher education in Russia is carried out from state and non-state sources. State funding of education has traditionally been dominant, but its size is insufficient for proper material and technical support of the educational process and scientific and technical activities. The problem of financing higher education institutions in Russia has become particularly acute due to the financial and economic crisis. On the one hand, the possibilities of budgetary financing of universities have decreased and, as a result, the salary level of the teaching staff has decreased, budget expenditures on scientific research have decreased, the suspension of budget financing of concessional loans for housing construction for scientific, pedagogical and teaching staff has decreased; on the other hand, the share of special fund funds earned by state higher education institutions themselves has increased relatively. At the moment, most of the mechanisms for financing higher education that have proven their effectiveness in developed countries are still not widespread enough in Russia or are not actively used by higher education institutions. In particular, the potential of grant financing, public-private partnerships, and the like is practically not used. Scientists call the practical absence in the country of the practice of state incentives for the participation of the corporate sector in the financing of higher education "structural distortions", although world experience shows that the micro-level awareness of the importance of the competence of employees, which encourages employers to invest in improving their educational level.

Application of Industrial Engineering Techniques for Continuous Improvement in Plastic Industry

Industrial engineering is a specified field of engineering that deals with the design, improvement, and installation of integrated systems such as of people, materials, and energy in industry. Industrial engineers use specialized knowledge and skills in the mathematical, physical and social sciences, together with the principles and methods of engineering analysis and design, to specify, predict, and evaluate the results obtained from systems and processes. As the present condition of the company is capable to some extent, but it is not sufficient as it looks. But it also faces some problems due to some improper arrangement like no proper storage system, proper material handling component, improper layout and improper arrangement of working tools. So to overcome these problems in the company, industrial engineering and its techniques can be used. By applying industrial engineering and its techniques there is improvement in companies existing situation and it helps to improve productivity and profit of the company. Problems identified in the company Atharva Moulds Pvt. Ltd. are storage department problem, company layout, material handling problem, 5s and safety issues. This problems are sort by using various engineering techniques such as, 5s, layout improvement, material handling, maintenance, safety, etc tools and productivity is improved. Keywords: Industrial Engineering, Productivity, Engineering Techniques,

Shape-Memory Properties of 3D Printed Cubes from Diverse PLA Materials with Different Post-Treatments

Poly(lactic acid) (PLA) belongs to the 3D printable materials which show shape-memory properties, i.e., which can recover their original shape after a deformation if they are heated above the glass transition temperature. This makes PLA quite an interesting material for diverse applications, such as bumpers, safety equipment for sports, etc. After investigating the influence of the infill design and degree, as well as the pressure orientation on the recovery properties of 3D printed PLA cubes in previous studies, here we report on differences between different PLA materials as well as on the impact of post-treatments after 3D printing by solvents or by heat. Our results show not only large differences between materials from different producers, but also a material-dependent impact of the post treatments. Generally, it is possible to tailor the mechanical and recovery properties of 3D printed PLA parts by choosing the proper material in combination with a chemical or temperature post-treatment.

Inline Non-Destructive Material Property Testing; The Future of Manufacturing

Across all industries, material specifications are tightening beyond previously understood process capabilities. Slight shifts in material grade, microstructure, heat treatment, or alloy composition can significantly impact long term material integrity. This study examines the feasibility of non-contact, 100% inline magneto-inductive testing on material/components destined for the automotive, aerospace, agricultural, and medical markets to ensure proper material quality standards. To test the hypothesis that material grade, carbon content, density, and alloy composition can be accurately tested in real time during production, an experiment was conducted utilizing magneto-inductive test instrumentation and encircling coil. Throughout this experiment, and proposed future state of manufacturing, 100% of material was tested. Results yielded clear confirmation in accordance with the hypothesis. This data driven subjective approach provided the ability to accurately, efficiently, and autonomously verify proper material grade had been used for the designated product. Ensuring proper material composition and material properties without slowing production using this testing method should be considered when improved quality is desired.

Optoelectronic and elastic response of fluorinated hexagonal boron nitride monolayer

The inherited insulating behavior of hexagonal boron nitride (h-BN) monolayer restricts its application in several optoelectronic devices, so finding a technique to reduce the bandgap allows it to possess the semiconducting functionality. Here, an experimentally feasible fluorinated hexagonal boron nitride (FBNF), a structurally, dynamically, and mechanically stable monolayer is reported by using density functional theory calculations. The significant geometrical transformation from planer h-BN to buckled FBNF softens the structure by retaining the mechanical isotropy and structural symmetry. Remarkably, the induced direct bandgap semiconducting behavior after fluorination enhances the optical absorbance and reflectivity reduces energy loss, creates strong optical anisotropy, and makes FBNF monolayer is a proper material in the optoelectronic and nanomechanical applications

Exoskeleton robots for lower limb assistance: A review of materials, actuation, and manufacturing methods

The field of robot-assisted physical rehabilitation and robotics technology for providing support to the elderly population is rapidly evolving. Lower limb robot aided rehabilitation and assistive technology have been a focus for the engineering community during the last three decades as several robotic lower limb exoskeletons have been proposed in the literature as well as some being commercially available. Numerous manufacturing techniques and materials have been developed for lower limb exoskeletons during the last two decades, resulting in the design of a variety of robot exoskeletons for gait assistance for elderly and disabled people. One of the most important aspects of developing exoskeletons is the selection of the most appropriate proper material. The material selection strongly influences the overall weight and performance of the exoskeleton robot. The most suitable fabrication method for material is also an important parameter for the development of lower limb robot exoskeletons. In addition to the materials and manufacturing methods, the actuation method plays a vital role in the development of these robot exoskeletons. Even though various materials, manufacturing methods and actuators are reported in the literature for these lower limb robot exoskeletons, there are still avenues of improvement in these three domains. In this review, we have examined various lower limb robotic exoskeletons, concentrating on the three main aspects of material, manufacturing, and actuation. We have focused on the advantages and drawbacks of various materials and manufacturing practices as well as actuation methods. A discussion on future directions of research is provided for the engineering community covering the material, manufacturing and actuation methods.