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

Collaboration between those working in product development and production is essential for successful product realization. The Swedish Production Academy (SPA) was founded in 2006 with the aim of driving and developing production research and higher education in Sweden, and increasing national cooperation in research and education within the area of production.

This book presents the proceedings of SPS2024, the 11th Swedish Production Symposium, held from 23 to 26 April 2024 in Trollhättan, Sweden. The conference provided a platform for SPA members, as well as for professionals from industry and academia interested in production research and education from around the world, to share insights and ideas. The title and overarching theme of SPS2024 was Sustainable Production through Advanced Manufacturing, Intelligent Automation and Work Integrated Learning, and the conference emphasized stakeholder value, the societal role of industry, worker wellbeing, and environmental sustainability, in alignment with the European Commission's vision for the future of manufacturing. The 59 papers included here were accepted for publication and presentation at the symposium after a thorough review process. They are divided into 6 sections reflecting the thematic areas of the conference, which were: sustainable manufacturing, smart production and automation, digitalization for efficient product realization, circular production, industrial transformation for sustainability, and the integration of education and research.

Highlighting the latest developments and advances in automation and sustainable production, the book will be of interest to all those working in the field.

Understanding the microstructural behaviour of materials during thermomechanical processing is a vital step towards optimizing the mechanical properties. One important aspect during forming processes, such as forging, is dynamic recrystallization (DRX), which sets the starting microstructure for the subsequent manufacturing steps. Here we investigated the DRX behaviour of Ni-base superalloy Haynes 282 during hot compression with a strain rate of 0.05 s−1 at 1080 °C, with care taken to minimize the effects of meta-dynamic recrystallization (mDRX) and adiabatic heating. Small DRX grains could be observed already at ε = 0.1, i.e. before the peak strain εp = 0.15. The DRX process accelerated significantly above ε = 0.2, and the material was fully recrystallized at ε = 1.5. Up to ε = 0.8 DRX occurred through continuous nucleation of new grains, whereas above ε = 0.8 the number density of DRX grains decreased and the increase in recrystallized fraction was due to growth of existing grains. Contrary to common assumptions of DRX nuclei being essentially dislocation free, many of the DRX grains contained pronounced dislocation substructures, even at small strains where they are not expected to have undergone deformation.

The evolution of microstructure and ductility has been investigated for Waspaloy after isothermal exposure between 5 and 1800s at 750–950 °C. Gamma prime (γ’) with 1.7 nm diameter is found in the mill-annealed condition, while precipitate-growth following a t1/3 relationship is observed for isothermal exposure. Grain boundary carbide networks are formed during isothermal exposure together with a rapid hardness increase. A drop in ductility is observed with the lowest values at 750 and 800 °C. Further ductility reduction during isothermal exposure correlates with the rapid hardness increase of Waspaloy. While grain boundary strengthening can compensate for the moderate age hardening observed for Haynes® 282®, the more rapid hardness increase due to γ' precipitation appears to be the dominating effect on ductility in Waspaloy. Carbide precipitation and growth kinetics are slower than those of Haynes® 282®, which further increases the relative effect of age hardening reactions on the ductility of Waspaloy.

Forging on an industrial scale often involves slow, size-limited cooling rates or high temperature hold times between, or after, deformation. This enables the dynamic recrystallization(DRX) initiated during forging to further progress under static conditions, a phenomenon called meta-dynamic recrystallization (mDRX). As mDRX will influence the final grain size, and thus properties, it is critical to understand and control it during processing. Here, we study the mDRX evolution in Ni-based superalloy Haynes 282 during post-deformation hold times of up to 120 s at 1080 ◦C afterpartial DRX. We find that mDRX is the dominating mechanisms responsible for the microstructure evolution the hold time. The very rapid mDRX kinetics in the initial stages suggest that quench delays (the time between the end of the deformation and the onset of the quenching intended to arrest the microstructure evolution) must be kept well below 1 s in order to allow reliable conclusions to be drawn from post-deformation microstructure investigations. A larger prior strain (larger DRXfraction) leads to faster mDRX kinetics and a larger final grain size. Larger strains leads to earlieri mpingement of the growing grains, which, in combination with smaller remaining deformed regions into which the grains can grow, limits the maximum size of the mDRX grains. We also note a close correlation between static recovery and stress relaxation during the hold time, whereas no such correlation between mDRX and stress relaxation can be observed.

This work presents the influence of microstructural constituents on liquation crack formation in the cast Ni-based superalloy, René 108. The investigation was divided into three parts: characterisation of the material's microstructure in pre-weld condition, hot ductility studies and analysis of liquation cracking induced by the gas tungsten arc welding process. Using advanced electron microscopy techniques it is shown that the base material in pre-weld condition is characterised by a complex microstructure. The phases identified in René 108 include γ matrix, γ' precipitates, MC and M23C6 carbides, and M5B3 borides. Based on Gleeble testing, it was found that René 108 is characterised by high strength at elevated temperatures with a maximum of 1107 MPa at 975 °C. As a result of constitutional liquation, the superalloy’s strength and ductility were significantly reduced. The nil strength temperature was equal to 1292 °C, while the nil ductility temperature was 1225 °C. The low ductility recovery rate (32.1), ratio of ductility recovery (36.2) and hot cracking factor (Rf = 0.05) values confirmed the low weldability of Renѐ 108. In the heat-affected zone (HAZ) induced by welding, constitutional liquation of mainly γ' precipitates, with a contribution of M23C6 carbides and M5B3 borides, was observed. The thin non-equilibrium liquid film, which formed along high-angle grain boundaries, led to crack initiation and their further propagation during cooling. The eutectic γ–γ' re-solidification products are visible on the crack edges.

homogenisation heat treatments. The hot ductility deteriorated significantly after long-dwell homogenisation heat treatments for 24 h at temperatures of 1120 and 1190 °C as compared with those treated at a short dwell time of 4 h at the same temperatures. The observed ductility deterioration was related to more extensive liquation along the grain boundaries caused by different mechanisms, e.g., liquation by solute segregation mechanism, Laves melting, constitutional liquation of MC carbides and supersolidus grain boundary melting, with the effect and extent depending on the solute changes after the homogenisation heat treatments. Furthermore, the role of Nb as the solute element and as the precipitate former, as well as the effect of minor alloying elements segregating along the grain boundaries, is discussed in connection to grain boundary liquation, which contributes to a better understanding of heat-affected zone liquation cracking susceptibility of cast ATI® 718Plus®. © 2020 The Authors

The equiaxed Ni-based superalloy Rene 108 was subjected to short-term annealing at five temperatures between 900 degrees C and 1100 degrees C. The phase composition, phase lattice parameters, microstructure, stereological parameters, and chemical composition of y´ precipitates were investigated by thermodynamic simulations, X-ray diffraction, scanning and transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Analysis of the y and y´ lattice parameters using the Nelson-Riley extrapolation function showed that the misfit parameter for temperatures 900 degrees C to 1050 degrees C is positive (decreasing from 0.32 to 0.11 pct). At 1100 degrees C, the parameter becomes negative, delta = - 0.18 pct. During the short-term annealing, gamma ‘ precipitates dissolution occurred progressing more rapidly with increasing temperatures. The surface fraction of y´ precipitates decreased with increasing temperature from 0.52 to 0.34. The dissolution of gamma ‘ precipitates did not only proceed through uninterrupted thinning of each individual precipitate, but also included more complex mechanisms, including splitting. Based on transmission electron microscopy, it was shown that after y´ precipitates dissolution, the matrix close to the y/y interface is strongly enriched in Co and Cr and depleted in Al.

Haynes 282 is a Ni-based gamma prime (gamma’) strengthening alloy with a balanced combination of high temperature properties and fabricability. This paper aims to study the evolution of the microstructure and hardness using a novel physical simulation method called arc heat treatment, followed by thermodynamic modeling of gamma’ precipitation. For the arc heat treatment, a steady state temperature gradient was generated using a stationary tungsten inert gas arc on a sample mounted onto a water-cooled chamber. The steady state condition ranged from room temperature to the liquidus and was achieved within the first few sec-onds. Aged and solutionized samples were arc heat treated for 1.5 min, 30 min, and 4 h. The experiments were complemented with temperature modeling, equilibrium calculations, and gamma’ precipitation simulations. A unique graded microstructure formed in the arc heat-treated samples. It consisted of a fusion zone with a dendritic microstructure; a region with the dissolution of all secondary phases (MC carbides, grain boundary carbides, and gamma’); a region with MC and grain boundary carbides; a gamma’ precipitation zone; and the base metal. The temperature range of the dissolution area extended to lower temperatures with increasing arc heat treatment dwell time. The gamma’ precipitation zone showed a distinct etching response coupled with high hardness. The hardness and the temperature range of the gamma’ precipitation zone increased with increasing arc heat treatment time. The gamma’ radii increased with increasing time and temperature. The gamma’ precipitation model, simulated with TC Prisma, showed very good agreement with the experimental results. Finally, the results were used to develop time-temperature precipitation and hardness diagrams. (c) 2021 The Authors. Published by Elsevier B.V. CC_BY_4.0

The influence of base metal conditions on the weld cracking behaviour of cast ATI 718Plus® is investigated by comparing 4 h and 24 h dwell time pseudo-hip homogenisation heat treatments at 1120, 1160 and 1190 °C with the as-cast microstructure. Scanning electron microscopy (SEM), X-ray diffraction (XRD) on electrolytically extracted powder and transmission electron microscopy (TEM) were used to identify Nb-rich secondary phases in interdendritic areas as the C14 Laves phase and Nb(Ti) MC-type carbides. All homogenisation heat treatments but the 1120 °C 4-h condition dissolve the Laves phase. A repair welding operation was simulated by linear groove multi-pass manual gas tungsten arc welding (GTAW). The Laves phase containing microstructures resulted in lower total crack length for heat affected zone cracking. Constitutional liquation of Nb(Ti) MC-type carbides is observed as a liquation mechanism in Laves-free microstructure, while thick liquid film formation due to the Laves eutectic melting could reduce the formation of weld cracks in microstructures containing the Laves phase.