Key Engineering Materials Vol. 1032

Abstract: Tailored machined blanks are sheets that feature heterogeneous thicknesses, allowing different areas of the final part to withstand distinct structural loads effectively. Conventional methods of tailoring the thickness of the final part, like chemical machining, are labour intensive processes that requires pre-masking and post cleaning of complex industrial component. The proposed method provides a cost-effective solution to manufacture light-weight components by simplifying the material removal compared to shaping intricate 3D parts. In fact, machining a flat blank is simpler than removing the material from complex 3D geometries. In this study, the feasibility of superplastically formed Ti-6Al-4V tailored machined blanks was analysed. Three industrial relevant design examples were developed for components forming with initial dissimilar thickness distributions. The results were examined through Finite Element (FE) simulation and experimentation. The FE simulations guided the design of these blanks. Two examples aimed to address the excessive thinning issue typically encountered with standard homogeneous thickness approaches, where specific regions in the part undergo maximum deformation. The blank designs were preserved with higher thicknesses in regions where maximum deformation was expected. The third example explored forming a structured pattern thickness distribution, incorporating thicker stiffeners covering the sheet in two perpendicular directions. Although the approaches differed, the goal of all three designs was to reduce the total weight of the part. The tailored blanks were manufactured via CNC machining from a 2.6 mm thick Ti-6Al-4V sheet, introducing variable thickness profiles. Subsequently, the blanks were superplastically formed in an SPF press. The successful forming of the parts demonstrated the feasibility of the tailored thickness blank approach that can enable the reduction in component weight. Also, this approach can help the industry to phase out chemical milling for the purpose of light-weighting and removing of excess material from post formed component. Importantly, the experimental trials showed good correlation with the FE simulations, emphasizing the crucial role of the FE tool in designing such components.

Abstract: In the aerospace industry, hot forming processes, using materials like Ti-6Al-4V titanium, are known for their complexity and cost. Senior Aerospace Thermal Engineering (SATE) has traditionally relied on a trial-and-error approach for new product introductions (NPIs), which, while effective, has led to significant time and resource expenditures. This paper examines the transition of SATE's NPI processes to a more efficient digital approach using AutoForm Forming simulation software. By doing so, SATE has been able to accurately predict forming outcomes, optimize tooling designs, and significantly reduce both the number of physical tryouts and the overall project costs. Two case studies are presented to demonstrate the practical applications of this digitalization, highlighting how important engineering decisions were taken. The paper concludes with an assessment of the impact on SATE's operations, noting improvements in development time, feasibility assessments, and overall production efficiency.

Abstract: This study assesses the impact of heat treatment on the microstructure and mechanical properties of AlSi10Mg alloy produced using the L-PBF method. The research compares the mechanical properties and microstructure of samples subjected to direct aging (heat treatment at 170 °C/2 h) and stress relief annealing (at 240 °C/2 h), which is below the temperature for silicon network decomposition. These results are then compared with the as-built state (without any heat treatment) after printing, serving as a reference. Tensile and hardness tests were used to determine the mechanical properties, while electron microscopy was employed to analyze the microstructure. The findings indicate that direct aging led to an increase in yield strength, tensile strength and hardness compared to the as-built state. In contrast, samples treated with stress-relief annealing exhibited comparable yield strength to the as-built state, but significantly lower tensile strength and reduced hardness. Notably, contrary to expectations, the ductility did not increase with decreasing strength and hardness; instead, it decreased.

Abstract: In this work, a TiNbCr alloy is proposed for solid-state hydrogen storage applications. The design of the alloy is based on the Hume-Rothery rules and the thermodynamic parameters ΔH_mix and Ω, while the alloy was conceived as single-phase with a BCC lattice. Samples were synthesized from alloy powder using additive technology and the DED method. The prepared samples were printed with different parameters and their structure and phase composition were subsequently analyzed. The possible influence of these printing parameters on the properties of hydrogen storage alloys is discussed.

Abstract: The article describes the results of the heat treatment of additively manufactured (AM) parts made of AISI H13 tool steel. Powder Bed Fusion (PBF), Direct metal Deposition (DED) and Metal Jet Printing (MJP) technologies were used for printing. Due to the different printing technology, the properties and microstructure of the parts also differ, which also affects the choice of heat treatment parameters. The results show a great sensitivity of quenching and tempering temperatures. Also, the differences in the final properties of parts produced by various AM technologies differ, both in terms of properties (hardness, wear resistance) and structure. This can have a significant effect on the performance of the molds and parts produced in this way.

Abstract: Ultrasonic welding is a process that has been in continuous development since it was first introduced in the 1940s. The process is widely used to join or reform plastic or metal materials using mechanical vibrations propagated at frequencies ranging from 20.000 Hz to gigahertz levels. These vibrations produce heat that melts the materials to be welded at their contact surface. In addition to the heat produced by the vibrations, a preset pressure is applied from the control panel of the welding machine to ensure perfect contact between the welded parts.[1] The ultrasonic welding process is time-efficient, taking less than 0.2 seconds in some cases, and does not damage the outer surface of the parts. The whole paper is structured in two parts, one theoretical and one practical, these parts are divided into six chapters. The first chapter of the paper explains the propagation process of ultrasound and what it actually is, as well as a brief history of ultrasound. In the second chapter there are generalities about ultrasonic welding and how this process is carried out and a history of ultrasonic welding. The third chapter introduces us to the subject of the paper, namely ultrasonic welding of plastics. Chapter four deals with the materials used to produce seat belts and their evolution over time. In chapter five we present all the equipment used for the case study. Chapter six is the case study and the explanation of all the steps performed to find out some results about ultrasonic welding of seat belt samples. Finally, I presented the conclusions drawn from the whole research process and the results obtained for the ultrasonic welding process of seat belts.

Abstract: In recent years, the field of ultrasound has seen remarkable advancements, mainly due to its close ties with the mechanical industry, recognized as the most dynamic industry of the last forty years. The application of ultrasound in the mechanical field has been guided by the advantages it offers, while the most significant advancements are related to the relatively low surface temperature compared to eroded surfaces, the evident localized accumulation, and the possibility of achieving dimensional improvements ranging from sub-millimeter values to centimeter values.

Abstract: This research focuses on optimizing ultrasonic welding technology for joining 3D printed metal composites. The study investigates the influence of various welding parameters, including ultrasonic frequency, amplitude, pressure and welding time, on the quality and strength of the welded joint. The research aims to identify the optimal welding conditions that ensure robust and reliable bonding of these complex materials, given their unique microstructural and mechanical properties. The findings will contribute to the development of efficient and reliable joining techniques for 3D printed metal composites, expanding their applicability in various engineering applications.

Abstract: This study's goal is to monitor and evaluate, without undertaking experimental trials, how different materials used in 3D printing behave when exposed to ultrasonic welding. Ultrasonic welding is a solid-state technique that eliminates the need for adhesives, solders, or mechanical fasteners by applying high-frequency ultrasonic acoustic vibrations to workpieces that are kept under pressure. When combining disparate materials, such metals and plastics, this method works especially well. This paper focuses on the theoretical analysis of ultrasonic welding for ABS and ONYX 3D-printed materials. This study intends to shed light on the compatibility, weld quality, and structural integrity of these materials under ultrasonic welding settings by examining current data and research. The results will advance knowledge about the suitability of ultrasonic welding for 3D-printed materials in manufacturing and industrial contexts.