This paper presents information and results relevant for the development of a laser heat treatment process suitable to improve manufacturing in high strength steel and high strength aluminium alloys. The challenges with manufacturing of such materials include springback effect and localised fracture. The study details heat cycle and their effect in metallurgical state and mechanical properties. Such laser induced heat treatment process is intended to improve the forming behaviour of metal parts in challenging metal forming conditions, in particular for the delay or avoidance of localised fracture. Results for strength, hardness and elongation properties are presented. It was concluded that it is possible to locally modify yield strength and hardness using process duration suitable for industrial applications. Suitable process temperature ranges and target heat cycles were identified. A positive effect of material softening was observed in both hardness and strength properties. However, in some cases a reduction of ductility is apparent which must be considered for targeted industrial applications. The dimension of the heat-affected zone was also considered as design variable for the industrial process development. Preliminary results were obtained in a development forming tool.

The effectiveness of local laser heat treatment technology to enhance the in situ formability of steels and aluminum alloys has already been widely acknowledged for the one-step forming of components with simple shape geometries. The present study demonstrates that this technology is also able to significantly improve the formability of a complex shaped multi-forming industrial part. An industrial grade advanced-high strength Dual-Phase DP1000 steel is used to analyze the multi-forming of a complex part to determine the most appropriate local laser heat treatment parameters and optimize in situ softening by correlating yield strength, ultimate tensile strength, elongation at fracture, strain hardening exponent and instantaneous strain hardening with local temperature dynamics during the laser treatment. Additionally, numerical simulation analysis using Autoform software is carried out to validate the selected heat affected zone and the in situ softening, ensuring that they are appropriate for improving the formability of the industrial part. These findings are then expanded to study the experimental forming of five in situ laser heat treated models, followed by comparative analysis with a benchmark. This study provides an insight and fundamental guidelines to perform in situ laser heat treatment on complex industrial parts leading to the production of the industrial multi-formed component with optimized formability.

This study presents information regarding the development of a localized laser induced heat treatment for aluminum alloys. Such process is intended to improve the forming behavior of aluminum parts in challenging metal forming conditions. This study details information on material, heat treatment parameters as well as results for strength, hardness and elongation properties. It was concluded that it is possible to locally modify yield strength and hardness using laser control parameters and process duration suitable for industrial applications.

Information is presented on the conceptualization, experimental study, and numerical process simulation of tailor heat treated aluminum alloy blanks. This concept is intended to improve the forming behavior of aluminum parts in challenging conditions. The implementation requires precise control of laser heat treatment parameters within a suitable industrial framework. The study details material properties, heat treatment parameters, and experimental results for the strength and elongation properties of an AA6063-T6 aluminum alloy. Constitutive modeling is applied using the Hocket–Sherby equation, which allowed us to establish a correlation between laser heat treatment maximum temperature and the corresponding material softening degree. Based on the generated flow stress–strain curves, a numerical simulation of a representative case study was performed with Abaqus finite element software highlighting potential improvements of tailor heat treated blanks (THTB). The influence and effectiveness of heat-affected zone (HAZ) dimensions and material softening were analyzed.

The structural strength and dynamic behaviour of transformer windings are mainly influenced by solid insulation material conditions. Since during transformer's operation the windings are subjected to dynamic forces and the pressboard used as insulation material tends to degrade, characterisation of its dynamic mechanical properties is necessary to improve control and early fault identification. In this study, the out-of-plane dynamic mechanical properties of pressboard are analysed as function of excitation frequency and ageing. A set of pressboard samples were subjected to an accelerated ageing test to obtain six different ageing conditions defined by their degree of polymerization according to IEC 60450. Then cyclic uniaxial compression tests were performed to determine the mechanical properties of pressboard by analysing the hysteresis curve as function of frequency and ageing. According to the experimental results, the pressboard can be modelled as a nonlinear elastic spring and a viscous damper connected in parallel. It is shown that ageing affects proportionally the stiffness and the damping. With the increase in frequency, the pressboard tends to increase its stiffness and mimics the behaviour of an ideal elastic material.

Visual inspection of components, subassemblies and final products is an essential step to ensure the quality control of ready-to-market electronic components. In many manufacturing plants, including Bosch Car Multimedia S.A., typically automated systems for automatic optical inspection (AOI) are implemented at several workstations to perform visual verification and validation in between critical production tasks. At Bosch Car Multimedia S.A., the AOI system includes a metallic support frame that accommodates a series of components for the function of AOI. The support frame is attached to a robotic arm for controlled movement. As the AOI is a rather fast-moving process, deformation of components may occur during monitoring due to the high acceleration of the robotic arm while operating. In addition to this issue, the existent AOI system includes a high number of components and connections which increase complexity for assembly and disassembly operations. This paper presents the redesign for enhanced performance and functionality of a AOI metallic support frame by resourcing to the generative design (GD) exploration method. Furthermore, additive manufacturing technology, based in selective laser sintering (SLS) of polymeric powders, was used for the production of a new lightweight and reliable version of an AOI support frame. The alternative AOI support frame configuration consists of a single consolidated polymeric component that enabled an overall weight decrease above 30% and a reduction of main components and total number of parts of approximately 89% and ∼77%, respectively.

In this work, the effect of ultrasonic vibration during solidification on the aging kinetics of an AlSi7Mg alloy is investigated. With the ultrasonic equipment coupled to the mold walls, melt treatment was performed by two approaches: (i) fully above liquidus (>635 °C); and (ii) in the full range between liquidus and solidus (630 °C→ 550 °C). Cast samples were then subjected to T6 heat treatment for different aging times. It is shown that indirect ultrasound treatment increases the cooling rate while active. The eutectic Si was refined and further modified when ultrasound treatment was performed in the semisolid state. Due to the significant release of solute during the decomposition of π-Al8FeMg3Si6 into fine β-Al5FeSi, this has a significant impact in the solution stage. Ultrasound treatment fully above liquidus decreased the underaging time to 50% and peak aging time to 25% without compromising strength. The results suggest aging kinetics are correlated with a higher vacancy density and solute enrichment which favors Guinier–Preston (GP) zone formation. These findings show a promising route to tailor the aging kinetics in these alloys by selectively modifying phases and cooling rates.

Silica aerogels are highly porous materials with exceptional thermal insulation performance. They become even more attractive if combined thermal and acoustic insulation is achieved. Silica aerogel composites reinforced with fibres are an ingenious way to surpass the fragility stemmed from the aerogel’s intrinsic porosity, and textile fibres are good sound absorption materials. Reclaimed fibres are a relatively low-cost feedstock and were obtained in this work exclusively through mechanical processes from textile wastes, thus promoting the concept of circular economy, namely for cotton, polyester and wool fibres. These reclaimed fibres were used as reinforcement matrices for silica aerogel composites obtained from sol–gel transformation of tetraethyl orthosilicate and isobutyltriethoxysilane/or vinyltrimethoxysilane precursors and dried at ambient pressure after silylation. Silica aerogel composites reinforced with reclaimed cotton fibres had the best sound absorption coefficient (a peak value of 0.89), while the polyester-reinforced composite exhibited the lowest thermal conductivity (k = ~24 mW m−1 K−1, Hot Disk). The better combined results on thermal and acoustic insulation were achieved by the wool-reinforced composites. The thermal conductivity values were less than 27 mW m−1 K−1, and the sound absorption coefficient achieved a peak value of 0.85. Therefore, the aerogel composites developed here can be selected for thermal or/and acoustic barriers by choosing a suitable type of fibre. Their design and preparation protocol followed environmental-friendly and cost-effective approaches.

In the present work, the effect of Al–5Ti–1B master alloy or ultrasonic melt treatment on α-Al nucleation mechanism and dendrite coherency point mechanisms of the Al–Si–Mg alloy have been studied through the thermal cooling curve and microstructural analyses. Results show that these refinement methods increased the nucleation temperature and reduced recalescence undercooling for the Al7SiMg alloy. For a processing temperature of 700 ºC, the ultrasonic melt treatment increased the difference between the liquidus and coherency temperatures ( T_N - T_DCP ) to 10 ºC. The T_N - T_DCP was further improved to 14 ºC when the same melt treatment was applied at 640 ºC. Ultrasonic melt treatment increased the solid fraction at coherency by 27

Low mass fractions (0.05 wt%) of SiC micro sized particles have been added to an A356 melt and dispersed by ultrasonic vibration to study their impact on the microstructural morphology of cast samples. It is shown that the ultrasonic melt treatment at 680°C can promote a homogenized distribution of the reinforcement while also degassing the melt and induces a moderate grain refinement. Even though SiC may act as a nucleant, its use did not induce a significant grain refinement relatively to ultrasonically treated unreinforced melts. Adding SiC microparticles, however, seems to enhance Eutectic Si modification, although it contributes to its slight coarsening at the expense of Mg2Si.

An A356 alloy is a classic casting light alloy, which is able to be processed into complex geometrical shapes with tailored static and dynamic mechanical properties. As a promising material to reduce fuel and energy consumption in future vehicle designs, there is an interest in understanding the impact of heat treatments on the damping capacity of this alloy. The Granato–Lücke theory is used to detail the forced vibration response in gravity cast A356. It is shown that a solution treatment enhances damping capacity in lower stress states (i.e., strain-independent regime) due to the increase in weak pinning length. However, in high-stress states (i.e., strain-dependent regime), peak-aged (T6) samples display higher damping capacity. This is proposed to be originated by releasing dislocations from weak pinning points, which start bowing in the precipitates that act as strong pinning points. Based on these results, it is shown for the first time that the selection of heat treatments to optimize damping in forced vibration is highly dependent on the expected stress–strain state and must be considered in the design of cast components.

Silica aerogel composites reinforced with reclaimed cotton fibers obtained from textile industry wastes are here presented. These fibers were obtained from fabric leftovers of textile clothing industry, using only mechanical processes for reverting wasted fabric scraps to elementary fibers. The syntheses were carried out following environmentally friendly solutions. The post-gelation silylation/washing steps were performed applying ethyl acetate, recognized as a non-hazardous solvent. The tetraethyl orthosilicate-based aerogel composites were developed with a co-precursor having a non-hydrolysable bulky branch, isobutyltriethoxysilane, aiming to reduce brittleness and increase hydrophobicity. The aerogel matrix composition used here, reinforcement conception and modification solvent are being presented for the first time in the literature. The composites, manufactured in small cylindrical-shape (diameter ~3 cm) and disk-shape (diameter ~9 cm and ~14 cm) were silylated with hexamethyldisilazane and ambient pressure dried. Thermal conductivities were assessed by non-stationary and steady-state methods, the later yielding values 25–37% lower, achieving a value as low as 21 ± 3 mW m–1 K–1. The composites exhibit a high degree of flexibility conferred by the embedded cotton fibers, that imparted as well good acoustic insulation, since at frequencies near 1300 Hz, the sound absorption coefficient is 0.8. Cotton fibers are well known by their moisture buffering. By taking advantage of that water adsorption/desorption, the thermal regulation ability of the aerogels is studied here as a novel application for these materials. At 85% of relative humidity, silica aerogel composites with ~15 wt% of cotton fibers adsorbed 2.6 wt% of moisture and the process reversibility was confirmed.

Machine end-effector kinematic analysis is critical to optimizing transporting components where inertial forces are the main loads. While displacements may be measured with relatively high accuracy in transportation equipment motors, the inertial forces in the transported components are seldom optimized. This is especially relevant in electronic component placement systems, where the components have a wide range of configurations (i.e., geometry and mass) and the deployment dimensional/geometric tolerances are remarkably good. The optimization of these systems requires the monitoring of the real position of the accelerometers relative to the measurement point of interest with sufficient accuracy that allows the assembly position to be predicted instantaneously. This study shows a novel method to calibrate this equipment using triaxial accelerometers on a surface mount machine to measure the end-effector accelerations and velocities in its planar motion. The dynamic equations of the system and the method for integration are presented to address the uncertainty on the exact position of the accelerometer sensors relative to the measuring point of interest exist and allow the position correction to optimize response and accuracy.

Cellular solids, as a class of materials, are known for a high strength to weight ratio. Their design into non-stochastic configurations is known to be beneficial for the tailor and control of their mechanical properties. The current developments on additive manufacturing allow a successful route to manufacture these scaffolds and gives a novel freedom in their design process. This study explores the deformation behavior of axisymmetric non-stochastic cellular solids, allowing the understanding of the mechanisms that enhance their mechanical properties relatively to regular extruded lattices. It is shown that axisymmetric samples display a circumferential deformation effect that distributed loads along the volume of the material. This effect, however, is more prominent in axisymmetric samples with auxetic behavior. The coupling of circumferential deformation and the dynamic density changes in auxetic samples generate an overall increase in modulus, collapse stress and energy absorption.

Ongoing industrial demand for lightweight materials has spiked the research interest in aluminium-based metal matrix composites for its specific properties. The amount of scientific publication available on the matter has led to the vast production of knowledge, which highlights the need for a systematic assessment if further progress is expected. In this paper, a systematic review of the published literature is conducted, according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, on the Scopus and Web of Science databases were used in the literature search, which was completed on the 29 August 2020. The data of the research work is structured in the particle pre-processing stage and the melt processing stage. The present review clarifies the combined pair-wise effect of particles and the melt treatment performed on their wettability or dispersive or de-agglomerative capability, which allows to achieve their final mechanical properties.

Carbon nanotube reinforced aluminum matrix composites are considered a promising solution for applications that require high specific mechanical properties. Even though there are numerous methods for their manufacturing, these are frequently based on powder metallurgy approaches, limiting the fabrication of components with significant volumes and complex shapes. Casting, as a manufacturing technique, is regarded as the most appropriate route to obtain complex-shaped components with a relative high microstructural quality. These techniques to obtain Al-CNT cast components is still challenging due to the agglomeration, lack of dispersion, reduced bonding and density of the CNTs in Al. To address these issues, CNTs are usually pre-processed by ball-milling with Al powder to promote bonding and disperse the reinforcement, however, these techniques are not really beneficial to casting approaches due to the increase of Al2O3 content that do not disperse within the Al alloy melts. This study proposes the use of Al spheres (~1 mm) in these ball milling techniques to prevent significant plastic deformation, the formation of Al flakes and the increase in Al2O3 content. It is shown that CNTs may be dispersed and bonded to the Al sphere surfaces. Results suggest that this is a promising novel technique to allow a successful implementation of casting-based routes to fabricate high-volume and complex-shaped Al-CNT components.

Aluminum-based cellular solids are promising lightweight structural materials considering their high specific strength and vibration damping, being potential candidates for future railway vehicles with enhanced riding comfort and low fuel consumption. The filling of these lattices with polymer-based (i.e., polyurethane) foams may further improve the overall vibration/noise-damping without significantly increasing their density. This study explores the dynamic (i.e., frequency response) and acoustic properties of unfilled and polyurethane-filled aluminum cellular solids to characterize their behavior and explore their benefits in terms of vibration and noise-damping. It is shown that polyurethane filling can increase the vibration damping and transmission loss, especially if the infiltration process uses flexible foams. Considering sound reflection, however, it is shown that polyurethane filled samples (0.27–0.30 at 300 Hz) tend to display lower values of sound absorption coefficient relatively to unfilled samples (0.75 at 600 Hz), is this attributed to a reduction in overall porosity, tortuosity and flow resistivity. Foam-filled samples (43–44 dB at 700–1200 Hz) were shown to be more suitable to reduce sound transmission rather than reflection than unfilled samples (21 dB at 700 Hz). It was shown that the morphology of these cellular solids might be optimized depending on the desired application: (i) unfilled aluminum cellular solids are appropriate to mitigate internal noises due to their high sound absorption coefficient; and (ii) PU filled cellular solids are appropriate to prevent exterior noises and vibration damping due to their high transmission loss in a wide range of frequencies and vibration damping.

Cellular materials are recognized for their high specific mechanical properties, making them desirable in ultra-lightweight applications. Periodic lattices have tunable properties and may be manufactured by metallic additive manufacturing (AM) techniques. However, AM can lead to issues with un-melted powder, macro/micro porosity, dimensional control and heterogeneous microstructures. This study overcomes these problems through a novel technique, combining additive manufacturing and investment casting to produce detailed investment cast lattice structures. Fused filament fabrication is used to fabricate a pattern used as the mold for the investment casting of aluminium A356 alloy into high-conformity thin-ribbed (~ 0.6 mm thickness) scaffolds. X-ray micro-computed tomography (CT) is used to characterize macro- and meso-scale defects. Optical and scanning electron (SEM) microscopies are used to characterize the microstructure of the cast structures. Slight dimensional (macroscale) variations originate from the 3D printing of the pattern. At the mesoscale, the casting process introduces very fine (~ 3 µm) porosity, along with small numbers of (~ 25 µm) gas entrapment defects in the horizontal struts. At a microstructural level, both the (~ 70 μm) globular/dendritic grains and secondary phases show no significant variations across the lattices. This method is a promising alternative means for producing highly detailed non-stochastic metallic cellular lattices and offers scope for further improvement through refinement of filament fabrication.

Ultrasonic vibration is a physical processing technique that has been gathering support as an environmentally friendly approach to degas light alloy melts. Since metallic sonotrodes promote melt inclusions due to erosion, ceramic sonotrodes have also been shown as a viable solution for ultrasonic melt degassing in industrial scales. This study shows that resonant ceramic sonotrodes are characterized by a complex low-amplitude radial eigenmode, while particle image velocimetry reveals that their efficiency depends on the angular direction. An approach based on synchronized kinematic translation was designed to optimize the degassing efficiency in ultrasonic approaches, assuring its angle with higher cavitation is always facing the center of the crucible. Results show that this approach can reach lower degassing thresholds (Hmin = 0.13 ml/100 g Al) at higher degassing rates, relatively to both Argon inflation (Hmin = 0.22 ml/100 g Al) and static Ultrasound (Hmin = 0.18 ml/100 g Al) methods. An enhanced grain refinement further supports the hypothesis that promoting a synchronized kinematic translation enhances the ultrasonic degassing efficiency. Considering these results, this approach is suggested as a reliable route to implement efficient ultrasonic degassing techniques in industrial light alloy melt treatment.