The reliability of electronics depends to a large degree on the reliability of the solder joints that interconnect the circuitry. Most solder joints contain tin as the majority phase to enable soldering at a temperature tolerable to the electronic components, but the tin must then operate at up to ~80% of its melting point due to resistance heating in service. As a percentage of melting point, this is as demanding as a turbine blade in an aeroengine and there is a similar ongoing desire to increase the operation temperature. In service, the joints regularly cycle between ~50 and 80% of melting point due to cycles of resistance heating and natural cooling, which causes thermal expansion and contraction of all phases and, therefore, thermal fatigue due to the mismatch in the coefficient of thermal expansion (CTE) at interfaces. Joints can also experience shock impacts, vibration and surges in current density, all of which must be withstood to ensure successful operation. Solder joints contain only up to a few tin grains and are highly heterogeneous with anisotropic properties. Therefore, to understand and predict the performance of solder joints it is necessary (i) to link mechanical measurements to the microstructure and crystallographic orientations in the joint and (ii) to develop crystal-level deformation and damage models that explicitly account for the evolving microstructure and link through to component and PCB-level models of thermal cycling, shock impact etc. Furthermore, to capitalise on the understanding generated by such an approach, it is necessary to develop the capability to reproducibly create the microstructures and orientations during the soldering process that are predicted to give optimum performance in service. To deliver this vision, we bring together expertise in controlling solidification kinetics in solder alloys, in-situ micromechanical measurement of crystal slip and slip transfer across interfaces, defect nucleation and growth, and micromechanical modelling at the crystal and microstructure level and at the component and board-level. With this team, we seek a step change improvement in the understanding, prediction and manufacturing of solder joints that are optimised for high reliability in high value UK industry and in the consumer electronics industry. The work addresses using solidification processing to generate single crystal and structurally representative units (e.g. intermetallic crystals (IMCs) with the desired facets, beta-Sn micro-pillars, or BGA joints with a single known beta-Sn orientation etc.). These are to be studied in carefully instrumented micromechanical tests to extract key material properties, and mechanistic understanding of defect nucleation at the crystal level. The properties and defect nucleation mechanisms are to be implemented in crystal plasticity models and, where necessary, discrete dislocation plasticity models to provide validated quantitative prediction of solder performance under thermo-mechanical and impact loading. The models are then to be exploited to design solder microstructures for optimal performance. The work will then develop methods to manufacture these optimum microstructures within the soldering process, building on recent advances in microstructure control made by the team. These optimised joints will then be tested and modelled such that optimally designed, high reliability joints may ultimately be achieved.

Additive Manufacturing (AM), also termed 3D printing, involves successively adding thin layers of new material formed by melting alloy powders or wires and solidifying them onto prior layers to construct 3D components. This process directly builds intricately shaped parts impossible to create using traditional techniques. Further, AM promises to be both more energy and materials efficient. Potential applications are far reaching, including biomedical, energy and aerospace. However, AM components can suffer from microstructural features that may lead to degraded properties, such as porosity and epitaxial grain growth. Porosity can form from gas bubbles entrained in the solidification front, leading to voids in the final built. Epitaxial grain growth occurs when new grains take on the crystal orientation of the previous layer, producing often undesirable direction dependent properties. We hope to control these features using magnetic fields acting on Thermoelectric (TE) currents. TE effects translate temperature variations at the junction of two conductive materials into electric current. They are well known in common applications such as Peltier coolers, TE generators for waste heat recovery and in thermocouples. In this proposal we aim use the interaction of thermoelectric currents and applied magnetic fields to generate fluid flow in the molten pool of metal that forms material in the AM process. This interaction is called Thermoelectric Magnetohydrodynamics, or TEMHD. Our feasibility studies indicate that TEMHD can transform the microstructure in AM components, preventing the formation of microstructural features such as porosity or epitaxial growth. We will show that thermoelectric effects are a natural and inherent part of AM processes, with high currents forming due to the huge thermal gradients encountered in AM. We will apply controlled external magnetic fields, causing these currents to interact and generate a Lorentz force that drives TEMHD flow. Our preliminary numerical predictions show that even a moderate magnetic field generated by permanent magnets is sufficient for TEMHD to dominate the melt pool hydrodynamics and that the flow magnitude is highly sensitive to the orientation and magnitude of the magnetic field. This sensitivity will enable us to modulate the heat, mass and momentum transport, enabling control of microstructural evolution, including epitaxial growth and gas entrainment. Our vision is to reveal the fundamental mechanisms that TEMHD introduces to AM and to then ultimately develop a pathway to exploit it in industrial applications producing improved and consistent material properties of components. To achieve these goals the investigators will employ state-of-the-art experimental and numerical modelling techniques. High speed in situ synchrotron X-ray radiography of the process will generate data for validation of the numerical model and provide benchmarks for the wider scientific community. The numerical model will capture the complex interactions in the melt pool and provide understanding of the complex physical mechanisms at work. Theoretical predictions from the model will guide the experimental programme, while direct observations will guide the numerical model development. With a validated numerical model, a parametric study of the magnetic field conditions along with key AM processing conditions will be conducted to determine conditions required to produce microstructures that give the properties required for each application. The ability to use TEMHD to design the microstructures will be demonstrated in the experimental programme. Throughout the project we will seek input from our industrial partners, and during the latter stages we will hold a workshop to develop translational pathways for scaling and implementing these techniques to the next generation of AM machines.

Additive manufacturing (AM) makes net-shaped, highly precise, and cost-effective components of intricate design with minimum waste. However, the AM industry faces many technical challenges in the production of high-quality parts due to intrinsic defects, e.g. pores, cracks, distortions and anisotropy. These microstructural discontinuities are related to the material properties and solidification behaviour upon the AM processing conditions, i.e. rapid melting and cooling. The current developments of AM focus mostly on the printing processing, mitigating intrinsic material's deficiencies by process control, such as laser power and scan speed, and much less on the material side, with a majority of the alloys being originally designed and tailored to suit other manufacturing routes, e.g. casting. The quality of AM parts is dominated by the properties and characteristics of the alloy feedstocks - vital aspects that are currently largely overlooked. As a consequence, there is a limited number of materials that are designed specifically for manufacturing high-quality AM components. The synergetic approach in this project is three-fold and aims to (a) develop a new class of hierarchically structured Al-based alloys with fine-tuned structures and compositions at both the nano- and micro-scale, which satisfy the requirements for cracking resistance, structure uniformity, reduced residual stresses and porosity, enabling a unique combination of properties and dimensional precision for AM; (b) test and optimise their performance upon AM using in situ and ex situ high precision characterisation methods; (c) validate the approach by manufacturing AM test parts with enhanced product quality and, hence, with improved properties and performance. Combining these three advances, we will deliver a new class of high-quality AM materials with lightweight, uniform structure and properties, high rigidity, thermal stability, and designed functionality; combining the best processing features of existing diverse alloy groups. While addressing the challenges of AM through dedicated material development, this proposal has a strong and credible pathway to impact other manufacturing processes, e.g. casting and powder metallurgy using the same alloy design paradigm.

The chemistry of the troposphere underlies a range of environmental issues, which have substantial societal and economic impacts. Whether it is a changing climate, a reduction in air quality affecting human health or the degradation of ecosystems due to air pollution the details of the chemistry determines the severity of the impact. Numerical models of atmospheric chemistry are essential to our ability to understand, predict and hence mitigate these problems. The description of the chemistry occurring within these models is known as the 'mechanism'. Different models use different levels of chemical complexity in deriving these mechanisms, depending on their individual foci. However, there is an overarching need for a 'gold standard' or benchmark mechanism, which contains as full a representation of our fundamental 'state of science' understanding of atmospheric chemistry as is possible. For the last decade this benchmark mechanism, both in the UK and internationally, has been the Master Chemical Mechanism (MCM). The MCM provides a highly comprehensive representation of atmospheric volatile organic compound (VOC) degradation chemistry, which is extensively used by the atmospheric science community in a wide variety of science and policy applications where chemical detail is required. The MCM is an internationally recognised resource, with registered users worldwide, and thus represents a highly regarded flagship facility for atmospheric science in the UK. Much of its success stems from the availability of the MCM database on the web, along with the provision of a range of tools to facilitate its use. However, both the MCM itself and its supporting infrastructure are now becoming dated. It is clear that the enormous task of bringing the entire mechanism fully up to date, and maintaining it in that condition, is becoming increasingly difficult within the resources and methods that are currently available. It is recognised, therefore, that sustainable development of the MCM as a whole requires a fundamental revision in the methods applied to its maintenance to ensure that updates/changes can be carried out thoroughly and efficiently, and which can be more readily sustained through changes of personnel in the future. Without such changes, it is probable that the MCM will stagnate, gradually fall from use and eventually become obsolete, and hence no longer a highly regarded flagship facility for atmospheric science in the UK. The MAGNIFY project puts in place a comprehensive strategic work plan (including a number of important scientific deliverables) in order to make the MCM more sustainable, updating its construction rules and opening it up more to community, building upon its success and maintaining it as the "gold standard" benchmark mechanism for atmospheric chemistry. This proposal will: 1) build a fully updated and revised mechanism development protocol, for the generation of a new version of the MCM (v4.0) 2) put in place a range of quality assurance methods to ensure high quality updates and changes into the future 3) develop an international community tasked with supporting the continual development of the MCM mechanism and framework. 4) investigate automated methods for mechanism generation that will reduce workload and error, ensuring responsive, efficient generation of mechanisms into the future 5) further develop and enhance the successful open access web platform used by the MCM for access, archiving and interrogation not only of the MCM and its successors, but also a range of mechanisms used by a range of NERC / MO / DEFRA supported activities and for a range of models world wide 6) provide a comprehensive evaluation methodology of all mechanisms stored in the system against the updated benchmark MCM and its successors with an emphasis on assessing those models currently being used for policy (air quality and climate) related work within the UK.

The automotive industry in the UK remains one of the key strategic sectors in the overall national R&D footprint, employing some 160,000 people (38000 in motor sport) [1]. The UK is home to a number of global OEMs representing the largest inward investment in the country's R&D through the establishment of significant technical centres. Influenced by the stringent emission mandates (Euro 4: Directive 98/70/EC and amendment: 70/220/EEC) and noise pollution targets (EU:DIRECTIVE 70/157/EEC and amendment: 2007/34/EC, USA: FHWA-HEP-06-020) improvements in engine efficiency have assumed a high priority with automotive manufacturers. An effective way is to reduce frictional (parasitic) and mechanical (errant dynamic) losses, accounting for 15 / 25 % of lost energy. Errant dynamic losses refer to inertial imbalance and structural deformation, also contributing to noise and vibration pollution. The largest mechanical losses are due to translational imbalance of pistons and rotational imbalance of the crank system, with increasing engine roughness due to demands for high output power-to-weight ratio. Engine roughness refers to structural vibration of lightly damped engine systems. Worst conditions for frictional losses arise under stop-start conditions or other transient events, where interactions between system dynamics and tribological behaviour of engine sub-systems play significant roles (Andersson [2]). Nearly half of the friction losses in internal combustion engines originate in the piston-ring-cylinder contacts, about 50% (Blau et al [3]), two thirds of which is attributable to the compression ring. Hitherto, interactions between frictional and mechanical losses have not received the fundamental analysis that they deserve. With increasing demand for high performance engines, the piston is subjected to even higher loads and, thus, increased losses. At the same time, engine development is driven by high fuel efficiency and output power-to-weight ratio, as well as reduced NOx and particulate emissions. These requirements frequently lead to conflicting demands put on combustion, system dynamics and tribological performance. It is significant to note that a mere 4% reduction in parasitic losses can lead to 1% improvement in fuel efficiency. Rapidly diminishing fossil fuel deposits in the UK's territorial waters and the difficulty of extraction, together with the adverse environmental impact of significant vehicular emissions, make improved fuel efficiency by reduction of parasitic losses a national imperative and a paramount objective. Whilst large national projects have been undertaken for development of efficient combustion strategies, a large consortium project has not hitherto been undertaken for tribology and dynamics of the piston-connecting rod-crankshaft sub-system which contributes significantly to engine losses. This project will bring together experts in the fields of dynamics, surface engineering, contact mechanics, lubricant rheology and tribology to collectively provide unique and novel solutions for this challenging multi-disciplinary problem of utmost importance to the UK automotive industry. An approach incorporating these inter-related disciplines within a unified analysis framework is referred to as multi-physics. This points to a single integrated project across all the interacting disciplines to deal with physics on a wide range of scales from large displacement dynamics to small thermo-elastic distortion of components and further down to micro-scale tribological contacts (such as EHD films, and asperity interactions) and onto the diminishing conjunctions of surface textured patterns with nano-scale interactions such as the molecular behaviour of lubricants due to their physical chemistry and free surface energy effects.