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| CSIRO | SOLVE | Issue 1 Nov 04 | |
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CAST METALS
Light Years Ahead
By Brad Collis
An Australian-developed alloy has answered the global car industry's call for lighter engines. The door has opened on the next generation of motor vehicles – lighter, stronger, cleaner and much more fuel efficient – following an Australian technology breakthrough that allows manufacturers to begin a new era of engine design.
USAMP is sponsored by the US Council for Automotive Research, which includes DaimlerChrysler, Ford and General Motors. USAMP established a magnesium engine development project several years ago which among other things required the development of a new magnesium alloy that could replace aluminium alloy in the production of lightweight engine blocks. They needed magnesium – 33 per cent lighter than aluminium, and stronger than the same weight of steel – to be turned into a stable, useable, material that met all the extreme physical demands of a combustion engine and could also be manufactured at a comparable cost to existing metals. Although there were some magnesium alloys that already met their technical specifications, these are prohibitively expensive because of the alloying elements and processes used in their production. In September this year USAMP announced that it had selected AM-SC1 as its preferred alloy for use in a major development project being sponsored by USAMP and the Department of Energy, to build and test a magnesium intensive V6 engine over the next two years. AM-SC1 has been developed by the Brisbane-based Cooperative Research Centre for Cast Metals Manufacturing (CAST). Cooperative Research Centres were established by the Australian Government, and CAST was also supported by the Queensland and Victorian governments.The alloy development team included researchers from CSIRO, the University of Queensland, Monash University and Australian Magnesium Corporation (AMC). The US announcement was made as an engine developed in a separate program, using the same magnesium alloy, nears the end of two-years of road testing in Europe. The development of the new alloy has given car makers a timely confidence boost as they face mounting pressure to produce environmentally cleaner vehicles through improved fuel economy and reduced emissions. CAST’s chief executive officer, Professor David StJohn, from the University of Queensland, says that using magnesium instead of iron in a car’s engine block could result in greenhouse gas savings of 2.75 tonnes of ‘CO2 equivalent’ over the car’s life. Professor StJohn says the development of a magnesium alloy that can be used in the high temperature conditions found in modern car engines has been the goal of international researchers for years:“That Australia was able to achieve this goal is testimony to our ability to assemble a team of the best magnesium alloy researchers from across the country.”
Head of the research team assembled through the CRC, Dr Colleen Bettles, from CSIRO Manufacturing and Infrastructure Technology (CMIT) in Melbourne, says a magnesium alloy engine is two-thirds the weight of a comparable aluminium alloy block. However, she says that aside from weight, the other critical issue that had to be resolved was minimising the long-term deformation that can occur at high running temperatures – this is the reason that cast iron car engines used to be returned to service centres to have everything tightened after an initial wearing-in. The aluminium alloy that replaced cast iron became the benchmark for minimal deformation, and a magnesium alloy had to at least equal that. The Australian magnesium engine program began in 1996 when a senior manager with Australian Magnesium Corporation (AMC), Ian Hartnell, realised car makers in Europe were seriously considering an engine made of magnesium. So he moved to form an alliance that joined Australian science with two European automotive supply companies. The project team that was formed included AMC, the large German aluminium engine manufacturer VAW, an Austrian engine designer, AVL, UK’s Magnesium Elektron Ltd and CAST. The objective was to develop a magnesium alloy engine that was at least comparable in performance and cost to an aluminium alloy engine. A prototype three-cylinder diesel engine made with AM-SC1 was developed and after extensive bench tests it was put into a Volkswagen Lupo to operate under road conditions for two years. In September the car had successfully travelled 56,000 of its planned 60,000 kilometres. Under the original agreement with VAW, plans were in place following successful road trials, to begin the development of magnesium engines on a commercial basis.These plans were shelved when VAW was bought by a Norwegian company, which subsequently withdrew from the project. Dr Bettles says the advantage of working with the European companies when they did was that the alloy could be developed in real time experiments concurrently with the engine design program. She explains that magnesium is a pure metal and to create the alloy you are trying to develop a recipe; a mix of magnesium and other metals, “and at the end of the day it has been our recipe that has created the new alloy that meets the auto makers’ needs. “It is a milestone that demonstrates our world-class capabilities.” Another crucial aspect of the development is the Australian product can be produced using a much cheaper process which brings down the cost of magnesium alloy towards that of aluminium. ... at the end of the day it has been our recipe that has created the new alloy that meets the auto makers' needs. Dr Bettles says the existing magnesium alloys that would do the job required by the automobile manufacturers are expensive to make, which is why those alloys have largely been limited to aerospace industries.The new alloy is considerably cheaper and still meets the requirements of the car manufacturers. Commercial rights to this new alloy belong to AMC, which is being restructured to form a new entity, Australian Magnesium Technologies (AMT). In its initial phase, AMT will concentrate entirely on further developing and commercialising this alloy, together with five other patented end-use magnesium technologies, which it developed with CAST for application in international automotive markets. There is potential for magnesium to make significant inroads into the automotive industry provided new costeffective technologies and alloys such as these can be developed and introduced effectively into this huge but cost-conscious and technically conservative market.AMT, in partnership with CAST, provides part of this solution. Professor StJohn says that regardless of the engine technology used, fuel economy and performance will always remain crucial: “So any advance in lightweight engines, where a large proportion of a car’s weight sits, is going to help improve the design of cars. “Once the engine is lighter, it allows a flow-on to the rest of the car. Magnesium is a logical lightweight alternative to traditional automotive materials, especially in power train components,” he says. “It has an excellent strength-to-weight ratio, high shock and dent resistance, and dampens noise and vibration more than either aluminium or steel.” CMIT’s general manager for transport technologies, Barrie Finnin, says that an important, wider, ramification of the technology is that it might give Australia a seat at the design table: “It should give us some influence over the choice of materials and processes used in automotive manufacturing, rather than always inheriting what someone else has developed,” he says. “It also means Australian manufacturers should have a competitive advantage by having the research scientists who are at the cutting edge of this field, on their doorstep.” CAST is a Cooperative Research Centre established under the Australian Government’s CRC program, with backing also from the Queensland and Victorian Governments. The alloy's development included researchers from CSIRO, The University of Queensland, Monash University and AMC. For further information contact: |
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In a significant global technology coup, an Australianinvented
magnesium alloy, AM-SC1, has been chosen by the United States Automotive
Materials Partnership (USAMP) to be the basis for its new low pressure/sand
cast engine research project. 
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