Scamans G.,Innoval Technology |
Scamans G.,Brunel University
Light Metal Age | Year: 2016
Significantly, it is now understood that Beilby layers determine many of the properties of aluminum alloy surfaces like their appearance and corrosion resistance and their electrochemical response during processing and testing. The deformed surface layer is of major importance to an industry that sells so many of its products based on their surface properties and corrosion performance. Cleaning and pretreatment of aluminum surfaces is not well understood, particularly for aluminum ABS, and successful pretreatment can only be achieved if sufficient cleaning is used to remove the influence of the deformed surface layer. The progressive removal of deformed surface layers can be directly measured by optical reflectance measurement and this technique can be used to optimize the cleaning process in production. The role of pretreatment is strictly only to provide adhesion and the key challenge for some of the more recently developed pretreatment systems is monitoring to show that the pretreatment is in place and that it has the required morphology. Electrolytic cleaning and pretreatment remains seriously under-exploited.
Han L.,University of Warwick |
Thornton M.,University of Warwick |
Boomer D.,Innoval Technology |
Shergold M.,Jaguar Land Rover
Journal of Materials Processing Technology | Year: 2011
AA5754 aluminium alloy was resistance spot welded (RSW) to produce 27 different joint stack-ups with differing process parameters and corresponding weld quality. Quasi-static joint strength was evaluated for three test geometries; lap-shear, coach-peel and cross-tension. The results derived from over 1000 samples demonstrate various fundamental relationships. For lap-shear strength, a strong relationship with weld nugget diameter was observed; whilst discrete strength levels were found for coach-peel test geometry, depending on the governing metal thickness of the parent sheet for the various stack-ups. For cross-tension strength; there is a relationship with nugget diameter; but data are sensitive to nugget periphery defects. These fundamental relationships provide a set of generalised design guidelines for RSW of aluminium that will have significant relevance to manufacturing communities. © 2010 Elsevier B.V. All rights reserved.
Zhou X.,University of Manchester |
Liu Y.,University of Manchester |
Thompson G.E.,University of Manchester |
Scamans G.M.,Innoval Technology |
And 2 more authors.
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2011
Near-surface deformed layers, which are characterized by nano-sized fine grains, are generated in aluminum alloys by hot and cold rolling. During the rolling processes, the alloy surface and near-surface regions experience a high level of shear deformation that results in significant microstructure refinement, leading to formation of near-surface deformed layers with microstructures different from that of the underlying bulk alloy. Two types of near-surface deformed layers are observed. Type A is characterized by fine grains with grain boundaries decorated by oxide particles; type B is characterized also by fine grains but with the grain boundaries free of oxide particles. The high levels of shear deformation result in dynamic recrystallization. Together with mechanical alloying, this is responsible for the formation of the near-surface deformed layer. Furthermore, the structure in the near-surface deformed layer can survive the typical annealing process particularly if the grain boundaries are pinned by oxide particles. © 2010 The Minerals, Metals & Materials Society and ASM International.
Holroyd N.J.H.,Bolivar |
Holroyd N.J.H.,Case Western Reserve University |
Scamans G.M.,Brunel University |
Scamans G.M.,Innoval Technology
Corrosion | Year: 2016
Aluminum alloy usage in maritime environments has fluctuated over the past 125 years with localized corrosion or environment sensitive cracking during service repeatedly preventing their full commercial exploitation, despite a series of innovations. Following a historical overview, discussion will focus on aluminum-magnesium alloys, highlighting current corrosion-related issues (e.g., intergranular corrosion, environment sensitive cracking) and potential opportunities to eliminate these problems in future commercial alloys. © 2016, NACE International.
Agency: European Commission | Branch: FP7 | Program: CP | Phase: ENV.2013.6.3-1 | Award Amount: 3.13M | Year: 2014
The EU wrought aluminium industry is based on the use of primary aluminium. Primary aluminium production is both energy and carbon intensive and EU production is rapidly declining. Secondary aluminium (post-consumer scrap) is either downgraded into low quality cast products, or exported. This scrap could be transformed into a low cost, low carbon feedstock for wrought product and high quality castings by the adoption of High Shear Processing (HSP) technology. This innovative new technology is based on a novel physical melt conditioning process that can be applied both to batch and continuous metal processing. It is based on leading edge research into the heterogeneous nucleation and growth in aluminium alloys, and its promotion by dispersed oxides. This research at Brunel University has demonstrated that the physical processing of liquid metals transforms oxides in melts from defects to active nuclei. This results in refined cast microstructures with significantly improved mechanical properties. The physically conditioned liquid can be used in all casting processes, including shape casting and the casting of rolling blocks or extrusion billets. The project will bridge the gap to industrialization through the involvement of a research-capable SME who will design and manufacture a prototype small industrial-scale HSP unit and then make recommendations regarding improved equipment design and likely process costs. Other SME partners will assist with economic modelling, through a life cycle analysis, which will comprise the costs of the process and the energy savings together with the impact in the carbon footprint. RecyCAL could have a major impact on the EU wrought and cast aluminium industry, leading to the consolidation of the primary and secondary industry sectors. The project could transform the EU aluminium metals cycle from one that is currently resource intensive to one that is sustainable.
Scamans G.M.,Innoval Technology |
Scamans G.M.,Brunel University
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2011
Intergranular sustained-load cracking of Al-Zn-Mg-Cu (AA7xxx series) aluminum alloys exposed to moist air or distilled water at temperatures in the range 283 K to 353 K (10 °C to 80 °C) has been reviewed in detail, paying particular attention to local processes occurring in the crack-tip region during crack propagation. Distinct crack-arrest markings formed on intergranular fracture faces generated under fixed-displacement loading conditions are not generated under monotonic rising-load conditions, but can form under cyclic-loading conditions if loading frequencies are sufficiently low. The observed crack-arrest markings are insensitive to applied stress intensity factor, alloy copper content and temper, but are temperature sensitive, increasing from ∼150 nm at room temperature to ∼400 nm at 313 K (40 °C). A re-evaluation of published data reveals the apparent activation energy, E a for crack propagation in Al-Zn-Mg(-Cu) alloys is consistently ∼35 kJ/mol for temperatures above ∼313 K (40 °C), independent of copper content or the applied stress intensity factor, unless the alloy contains a significant volume fraction of S-phase, Al 2CuMg where E a is ∼80 kJ/mol. For temperatures below ∼313 K (40 °C) E a is independent of copper content for stress intensity factors below ∼14 MNm -3/2, with a value ∼80 kJ/mol but is sensitive to copper content for stress intensity factors above ∼14 MNm -3/2, with E a, ranging from ∼35 kJ/mol for copper-free alloys to ∼80 kJ/mol for alloys containing 1.5 pct Cu. The apparent activation energy for intergranular sustained-load crack initiation is consistently ∼110 kJ/mol for both notched and un-notched samples. Mechanistic implications are discussed and processes controlling crack growth, as a function of temperature, alloy copper content, and loading conditions are proposed that are consistent with the calculated apparent activation energies and known characteristics of intergranular sustained-load cracking. It is suggested, depending on the circumstances, that intergranular crack propagation in humid air and distilled water can be enhanced by the generation of aluminum hydride, AlH 3, ahead of a propagating crack and/or its decomposition after formation within the confines of the nanoscale volumes available after increments of crack growth, defined by the crack arrest markings on intergranular fracture surfaces. © 2011 The Minerals, Metals & Materials Society and ASM International.
Hall A.,Innoval Technology |
Scamans G.,Innoval Technology
Light Metal Age | Year: 2011
The article tracks the paths taken by the various manufacturers of aluminum ABS in Europe while reviewing the current situation at each of these plants. It also considers the possibilities for the development of aluminum for automotive application in the future. Realizing that further consolidation was required for them to remain a competitive force in the world industry, Alusuisse held talks with VAW and their parent, Viag AG, in a move to form a joint venture operation. These talks proved unproductive, but in August 1999 the company reached an agreement with Alcan in Montreal and Pechiney in Paris for a merger of the three companies to form a new company. Aleris acquired the aluminum operations of the Corus Group of the U.K. in 2006. Corus had merged with the Dutch Hoogovens Group in 1999, who had previously taken over the operations of Kaiser Aluminum Europe in 1987, including their plant at Koblenz, Germany.
Agency: GTR | Branch: Innovate UK | Program: | Phase: Collaborative Research & Development | Award Amount: 340.04K | Year: 2012
Al-Si casting alloys have a wide range of applications in the automotive sector. These alloys contain high levels of silicon, which causes large grain sizes. Refining the grain size is crucial to achieve the superior performance castings. Grain refiners used for non-cast aluminium alloys are ineffective in cast aluminium due to the silicon levels. Brunel’s new grain refiner (BGR) provides a much needed solution to this problem. The BGR has the potential to transform practices in the Al-Si casting industry by enabling innovative, cheaper, and simpler casting to produce high performance cast structures. Delivering benefits to a wide range of casting techniques, it should enable castings with superior properties, thereby, allowing aluminium to replace some steel components in the automotive sector. The project aims at applying grain refiner to produce high performance Al-Si alloys cast components for automotive applications.
Agency: European Commission | Branch: FP7 | Program: CP-IP | Phase: NMP-2009-3.2-1 | Award Amount: 8.31M | Year: 2010
The project concept is to combine nanoreactor technology with multisite solid catalyst design to achieve a safer, cleaner and intensified chemical production. The project ideas are the following: (i) From micro- to nano-reactors. Actual microreactor have channels of micrometric size. We will develop a new concept based on the use of nanometric size channels. (ii) Vectorial pathway for multisite catalytic reactions. A limit in cascade (or domino) reactions is that there is no possibility to control the sequence of reactions of transformation of a reactant in a multisite catalyst. The concept of vectorial pathway for multisite catalytic reactions is based on the idea of an ordered sequence of catalytic sites along the axial direction of the channels of a membrane, in order to control the sequence of transformation. (iii) Dynamic nanoreactor. The concept of dynamic nanoreactor is based on the transient generation of toxic reactants inside the nanoreactor and the immediate conversion, in order to eliminate the storage of these reactants (which is minimized, but not eliminated in on-site or on-demand approaches). The project concept is that the implementation of innovative and safer pathways for sustainable chemical production requires making a step forward in the development of catalyst-reactor design along the lines indicated above. The project applies above ideas to three reactions of synthesis of large-volume chemicals which are relevant example of innovative pathways for sustainable chemical production: (1) direct synthesis of H2O2, (2) PO synthesis with in-situ generated H2O2 and (3) solvent-free synthesis of DPC with in-situ transient generation of phosgene. The consortium has a clear industrial leadership, with sixth major companies and two SMEs, and four academic partners, plus the participation of the durable institution of the NoE IDECAT.
Agency: GTR | Branch: Innovate UK | Program: | Phase: Collaborative Research & Development | Award Amount: 262.00K | Year: 2012
The aim of the REPLICAL project is to develop a new roll to roll production process route using aluminium rollers for continuously manufacturing polymer film with similar anti-reflective properties to those of a moth-eye. Proof-of-concept for the nanoreplication process has been demonstrated. We intend to scale-up roller manufacture to a commercial scale and to demonstrate the manufacture of a range of moth-eye film products for the display and touch-screen markets. Roller manufacture requires special aluminium sheet as starting material and innovative surface finishing to produce rollers with the surface for direct polymer replication for anti-reflective properties. The innovative roll-to-roll nanoreplication process will lead to a step-change in UK competitiveness through a novel manufacturing route for a wide range of biomimetic functional polymer films.