The present study unveils a comprehensive analysis of ultrasonic welding bonding mechanisms for multilayer copper foil combinations, notably Electrolytic Tough Pitch (ETP) copper, in pouch cell-based battery packs. Pouch cell-based battery packs utilize multilayer copper foils for their tabs, requiring a strong connection to the busbar to meet strict requirements for joint strength and electrical conductivity. Ultrasonic welding is employed for this purpose, specifically focusing on analyzing the bonding mechanisms of multilayer copper foil combinations. This study investigates the effects of key weld parameters like weld time, weld force, and weld energy on microstructure. Micrographs are analyzed to categorize welds as ‘under-welded’, ‘well-welded’, or ‘over-welded’. Light optical microscopy identifies various joint behaviors and weld defects such as swirls, interfacial waves, microbonds, interfacial gaps, voids, and delamination. A pattern in the distribution of certain joint features is noted, dividing the weld nugget into three regions: top, middle, and bottom. The top and bottom regions show signs of material mixing, while the middle region is characterized by microbond formation.

NiCrAlY as a coating is often used to improve the high temperature strength and oxidation performance of superalloys. Traditionally these coatings are deposited using various thermal spray techniques. Producing these coatings with Additive Manufacturing methods like the Directed Energy Deposition with Laser Beam (DED-LB) process improves the coating-substrate bonding. Subsequently, it enhances the high-temperature capability. To achieve this, understanding the correlation between process parameters and microstructure is crucial. The commercially available NiCrAlY powder is deposited on the alloy 718 substrate in this study. A two level three factor design of experiments was conducted for single track and three-layer track depositions. Statistical analysis was used to understand the effect of the primary process parameters (laser power, scan speed and powder feed rate) on the geometrical characteristics such as height and width of the deposition, and dilution of the substrate. Microstructural studies revealed the transformation in grain morphology from intra-dendritic mode of precipitation to inter-dendritic mode of precipitation with dilution from the substrate. From the Energy Dispersive Spectroscopy analysis, the formation of γ-Ni matrix phase and β-NiAl precipitate phase was confirmed. Samples with low dilution exhibited high hardness in accordance with high β phase content. In the three-layer tracks, the presence of hard and brittle β phase along the dendritic boundaries led to surface cracking due to stress build up.

The PH 13-8 Mo family of steels belong to the martensitic precipitation hardening stainless steels (MPHSSs) category, which exhibits a good combination of mechanical properties and corrosion resistance. Additive manufacturing (AM) offers advantages, including reduced material waste and the capability to produce complex, near-net-shape parts. Consequently, the application of AM techniques to the PH 13-8 Mo family is being increasingly explored across various industries. This review paper presents the existing literature on the topic and provides an overview. The review starts by presenting information about the PH 13-8 Mo family, including microstructure, chemical compositions, heat treatments, and mechanical properties. Afterwards, the work focuses on presenting the microstructure and resulting properties of PH 13-8 Mo family processed by three different additive manufacturing processes: Powder Bed Fusion using a Laser Beam (PBF-LB), Directed Energy Deposition using an Electric Arc (DED-Arc), and Directed Energy Deposition using a Laser Beam (DED-LB), both in their as-built condition and following post-processing heat treatments. The review concludes with a summary and outlook that highlights existing knowledge gaps and underscores the need for further research to tailor the microstructural evolution and enhance the properties. The findings indicate that AM of the PH 13-8 Mo family has the potential for industrial applications, yet further studies are necessary to optimize its performance.

The mechanical compression properties of C250 maraging steel fabricated by directed energy deposition (DED), in the as-deposited and post-fabrication heat-treated conditions, are investigated under quasi-static loading conditions. The microstructure of the material is studied using analytical transmission electron microscopy and a comparison is made between the DED fabricated and conventionally produced wrought materials. The results reveal that the DED fabricated material, in the as-deposited condition, exhibits lower yield and ultimate compressive strengths compared to the commercially heat-treated wrought alloy, due to the absence of strengthening precipitates and the presence of a retained austenite phase. However, post-fabrication thermal treatment significantly improves the compressive strengths of the as-processed material to levels comparable to those of the conventionally produced wrought material. This is attributed to the formation of nano-sized Ni3Mo strengthening precipitates, a reduction in the amount of austenite phase, and the refinement of prior-austenite grains during the thermal treatment. Moreover, the DED fabricated material, in the heat-treated condition, with the presence of an austenite phase shows higher ductility than the commercially heat-treated wrought material. 

Welding or brazing of metals to ceramics often leads to failures under aggressive conditions due to abrupt changes in physical, chemical, and thermal properties at the metal-ceramic interface. Metal-ceramic Functional Graded Materials (FGMs) replace the strict interface with a gradual transition of composition and properties, which protects the material from failures. The powder-blown Laser-Directed Energy Deposition (DED-LB) is one of the widely known Additive Manufacturing (AM) processes that offer unique features like developing FGMs and multi-material structures. Various studies have been conducted to process metalceramic FGMs using the DED-LB process but significant differences in thermal properties, varying laser-material interactions, and the possibility of formation of complex reaction products make the processing of metal-ceramic FGMs challenging. This study aims to understand the effect of laser power on a ceramic substrate, and its interaction with a metal powder introduced in the melt pool. A single track of nickel-based superalloy Alloy 718 powder was deposited on an Alumina substrate with different laser powers. The deposition was performed with and without substrate pre-heat to understand the effect of pre-treatment on deposition. Metallographic analysis was performed to reveal the microstructure of the resolidified metal mixed ceramic region

Duplex stainless steel (DSS), specifically the 2209 grade, is increasingly employed in additive manufacturing, particularly in processes like directed energy deposition using a laser beam with wire (DED-LB/w). However, a significant challenge arises when DSS faces brittleness within the temperature range of 250–500 °C. This study employs advanced characterization techniques, including atom probe tomography (APT) and transmission electron microscopy (TEM), to investigate DSS embrittlement after aging at 400 °C for up to 1000 h. The hardness analysis revealed that the higher Ni content in DED-LB/w-fabricated DSS cylinder promotes the age hardening compared to 2205 wrought DSS plate. Furthermore, APT and TEM demonstrated that, alongside the decomposition of ferrite into Fe-rich (α) and Cr-rich (αʹ) phases, clustering of Ni, Mn, and Si atoms contributes to the embrittlement. Although the Ni-Mn-Si-rich clusters could suggest nucleation of G-phase, the G-phase crystal structure was not observed by TEM. This might be attributed to the short aging time or limitations in the characterization technique. This work underscores the impact of characterization techniques on the measurement of spinodal decomposition, with APT providing capability of detecting nanometer sized clusters. By elucidating the complexities of 475 °C-embrittlement in DED-LB/w DSS, this study offers valuable insights for industrial applications and a deeper understanding of age hardening in duplex DSSs under specific manufacturing conditions. 

Wire + arc additive manufacturing (WAAM) is a state-of-the-art and highly efficient technique utilized to produce near net-shaped products on a large scale, employing a layer-by-layer approach. This research used pulsed current mode welding for single-layer bead-on-plate experiments to optimise the process parameters for WAAM of Hastelloy C-276. The effect of process parameters including pulsed current, pulsed frequency, and pulse duty cycle was systematically investigated on the weld appearance, depth of penetration, layer width, and layer height. The optimisation of single layer experimental runs was conducted using Box-Behnken designs (BBD) and the response surface method to construct several regression models. An analysis of variance was employed to validate the accuracy of both the measured and generated models. The BBD results indicate that interactions have a more significant impact on the peak current parameter than the resulting impact of pulse duty cycle and frequency. Validation tests were performed on the model with the optimal process variables that were identified, and its mechanical and metallurgical properties were analysed. Macrostructure and microstructural analysis of the single layer showed that the specified process parameters led to acceptable base metal fusion and bead is free from cracking. There was a considerable decrease in elemental segregation while using the pulse mode technique. Finer grain structure and reduced microsegregation enhance the hardness. Further residual stress (RS) at weld bead and base plate was 213 MPa and −240 MPa. Nonhomogeneous heat transfer during welding affects RS compressive and tensile characteristics. WAAM printing quality requires precise control of LH, LW, and DOP. This research aimed to propose suitable parameter values for manufacturing WAAM component for usage in chemical processing, nuclear, marine, and industrial settings by using unique pulsing features. 

Key performance indexes (KPIs) in various forms have always been used in one way or another in the production and processing of raw materials. The need for KPIs was accentuated with the advent of industrialism in the western world. The way and strategy of manufacturing industrial products has been divided into several so-called developmental transformations. Primarily after the depression of the 1930s and after the Second World War, a way of working and a basic view was gradually created that has resource efficiency and goal achievement as a fundamental idea. This publication describes how KPIs can be used in higher education to create a sustainable academy to meet challenges in industry and society over time. This with a focus on sustainability and continuity as well as a strategic integration between the academy’s various missions. These missions consist of teaching, research and collaboration. Furthermore, according to the Higher Education Ordinance, teaching shall rest on a scientific basis and, when appointing senior positions, equal weight shall be attached to the merits that can be linked to teaching and research. In addition to teaching and research, collaboration must be conducted with the surrounding society. Society places increasing demands on the knowledge conveyed in teaching to harmonize with current needs and to prepare for future needs and challenges. A starting point for the publication is that needs and challenges can best be met through a conscious and strategic integration between the academy’s various missions. Another aspect that is highlighted in this publication is the importance of strengthening the collaboration between basic subjects and more applied and industry-related subjects, which provides renewal in the applied subjects at the same time as the basic research can be utilized at a higher rate. In an industrial perspective, a more continuous TRL scale is obtained, which provides a more effective implementation of research results. A development path that strengthens the Academy’s mission areas is the principle of affiliation of personnel from industry and other sectors of society and increased admission of industrial doctoral students and other external doctoral students. In order to monitor the development of the respective mission areas of academia and its integration, the use of KPIs will be addressed. A discussion of their benefits will be highlighted but also the associated difficulties, especially when conditions change. The conducted literature study shows that there are very few or rather no found publications dealing with KPIs for the integration of the Academy’s different missions. KPIs are well developed for higher education in terms of its implementation and associated economics. Corresponding published work related to KPIs in research deals primarily with conventional academic bibliometrics. 

The fusion zone microstructures in K-TIG-welded and post-weld solution heat-treated new superalloy VDM Alloy 780 were examined. In addition, the kinetics of the base metal grain growth during solution heat treatments were analyzed. (S)TEM analyses show that major interdendritic microconstituents formed in the fusion zone due to elemental microsegregation are MC carbides and coarse irregularly shaped Laves phase. Additionally, minor secondary interdendritic phases are found to include γ′, γ″, and tiny plate-like Laves particles. To prevent any potential deterioration of mechanical properties caused by the irregular Laves phase, post-weld solution heat treatments (PWSHTs) at 954 °C to 1060 °C/1 hours were performed to remove the Laves phase. PWSHT at 954 °C only partially eliminates the Laves particles while forming an abundance of interdendritic δ/η phase. Laves phase is dissolved entirely without forming δ/η platelets after PWSHT at 1060 °C. It is proven that Laves eutectics in VDM Alloy 780’s fusion zone can be eliminated through PWSHT without significantly coarsening the base metal’s grain size in comparison to Alloy 718 as a result of substantial grain growth inhibition likely caused by solute segregation at grain boundaries.