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- Bjurenstedt, Anton, et al.
(författare)
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Assessment of Quality when Delivering Molten Aluminium Alloys Instead of Ingots
- 2013
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Ingår i: Materials Science Forum. - : Trans Tech Publications. - 0255-5476 .- 1662-9752. - 9783037857663 ; 765, s. 266-270
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Tidskriftsartikel (refereegranskat)abstract
- Recycled aluminium alloys manufactured at Stena Aluminium, in Älmhult, Sweden, are delivered in special designed transport containers, called thermoses. Thermoses are best described as an insulating layer protected by a steel cover with a heat loss of about 5 degrees/h. Three thermoses are transported by a truck, giving the possibility for a total capacity of about 24 tonnes delivered aluminium just-in-time to the foundry. By delivering a full load of liquid aluminium, about 2 tonnes of carbon dioxide emissions are saved, compared with delivering ingots. The aim of the paper is to assess the quality benefits, in terms of inclusions sedimentation and mechanical properties, assured by delivering aluminiummelts instead of ingots. The results indicate that materials produced by just-in-time melt delivery have slightly improved quality compared to ingots. The trends are explained in terms of quality, density and bifilm indexes, based on microstructural observations as well as tensile test data analysis.
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| 2. |
- Ceschini, Lorella, et al.
(författare)
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Effect of Fe content and microstructural features on the tensile and fatigue properties of the Al-Si10-Cu2 alloy
- 2012
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Ingår i: Materials & design. - : Elsevier. - 0264-1275 .- 1873-4197 .- 0261-3069. ; 36, s. 522-528
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Tidskriftsartikel (refereegranskat)abstract
- As the automotive industry has to meet the requirements of fuel efficiency and environmental concerns, the use of aluminium alloys is steadily increasing. A number of papers have been published about the correlation between microstructure and mechanical properties of the widely used A356/A357 aluminium alloys, while relatively few data are available on others hypoeutectic Al-Si alloys, such as Al-Si-Cu alloys with higher Si content. In this work the effect of different amounts of Fe and Mn on the tensile and fatigue behaviour of the AlSi10Cu2 casting alloy was studied. The reason of this study comes from the fact that cast components are mostly made by secondary Al alloys that inevitably contain Fe, which in turn forms intermetallic compounds, negatively affecting the mechanical behaviour of the alloy. Fatigue specimens were subjected to hot isostatic pressing (HIP) before tests, in order to eliminate the internal pores (gas pores and interdendritic shrinkages) and therefore to solely investigate the effect of microstructural features, rather than solidification defects, on the fatigue propagation stage. The microstructural characterization of the alloy was carried out by optical and scanning electron microscopy. Proof and ultimate tensile strength, as well as fatigue life of the investigated alloy were greatly enhanced by high Fe and Mn content, which reduced the micro-crack propagation rate; on the contrary Fe, without Mn, negatively affected the elongation to failure.
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| 3. |
- Ceschini, Lorella, et al.
(författare)
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High temperature tensile behaviour of the A354 aluminum alloy
- 2014
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Ingår i: Materials Science Forum. ; 794-796, s. 443-448
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Tidskriftsartikel (refereegranskat)abstract
- The high temperature tensile behaviour of the A354 casting aluminum alloy was investigated also evaluating the influence of secondary dendrite arm spacing (SDAS). Cast specimens were produced through a gradient solidification equipment, obtaining two different classes of SDAS, namely 20-25 µm (fine microstructure) and 40-50 µm (coarse microstructure). After hot isostatic pressing and T6 heat treatment, the samples underwent mechanical characterization both at room and high temperature (200 °C). Results of tensile tests and hardness measurements were related to the microstructural features and fractographic characterization, in order to investigate the effect of microstructure and high temperature exposure on the mechanical behaviour of the alloy.
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| 5. |
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| 6. |
- Jarfors, Anders, et al.
(författare)
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Metal casting
- 2014
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Ingår i: Handbook of Manufacturing Engineering and Technology. - London : Springer. - 9781447146698 ; , s. 309-410
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Bokkapitel (refereegranskat)
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| 9. |
- Olofsson, Jakob, 1980-
(författare)
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Microstructure-based Mechanical Behaviour in Structural Analyses of Cast Components
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the process of developing cast iron and cast aluminium components, the co-operation between product development and production is important. On the engineering level, this co-operation is limited already in the product development phase e.g. by the lack of established methods to consider the mechanical behaviour of the completed component.This thesis aims to increase the possibilities for co-operation in the product realisation process between product development and production by enabling the use of predicted local mechanical behaviour in structural analyses of cast components. A literature review on existing simulation methods and a work on characterization of mechanical behaviour from microstructural features are performed to identify important knowledge gaps. A simulation strategy is formulated that is able to predict local mechanical behaviour throughout the entire component and incorporate the behaviour into a Finite Element Method (FEM) simulation of the structural behaviour of the component. In the simulation strategy, the component specific microstructure-based mechanical behaviour is predicted using a casting process simulation. A computer program is developed to create FEM material definitions that capture the local variations in mechanical behaviour throughout the component.The relevance of the simulation strategy is demonstrated for a ductile iron component. It is found that the local variations in mechanical behaviour result in a stress-strain distribution in the component that a homogeneous material description fails to express. Residual stresses affect the mechanical behaviour at low loads. At higher loads, however, the accuracy of the simulation is determined by the local variations in mechanical behaviour. Using a material reduction technique, the local mechanical behaviour can be incorporated without increasing the FEM simulation time.
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| 10. |
- Olofsson, Jakob, 1980-
(författare)
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Simulation of Microstructure-based Mechanical Behaviour of Cast Components
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the process of developing cast iron and cast aluminium components, a high level of co-operation between product development and production is of great importance. From an engineering standpoint, this co-operation is limited early in the product development phase by e.g. a lack of established methods for the consideration of local variations in the mechanical behaviour of a finished component.This thesis aims to increase the possibilities for co-operation between product development and production during the product realisation process by introducing and studying the use of predicted local mechanical behaviour in structural analyses of cast components. A literature review of existing simulation methods and a work on characterisation of mechanical behaviour from microstructural features have been performed to identify important knowledge gaps. A simulation strategy has been formulated which is able to predict local mechanical behaviour throughout the entire component, and to incorporate this into a Finite Element Method (FEM) simulation of the structural behaviour of the component. In the simulation strategy, componentspecific microstructure-based mechanical behaviour is predicted using a casting process simulation. A computer program was developed to create FEM material definitions which capture the local variations in mechanical behaviour throughout the component. Using a material reduction technique, the local mechanical behaviour can be incorporated without increasing the FEM simulation time.The relevance of the simulation strategy was experimentally verified on cast aluminium samples, where the strain field was observed using Digital Image Correlation (DIC). It was found that the local variations in mechanical behaviour cause a stress-strain distribution that deviates from that predicted by a homogeneous material description, indicating the importance of calculating with and including such variations in material behaviour in FEM simulations. Numerical investigations demonstrate the strategy’s relevance for predicting the behaviour of cast aluminium and ductile iron components.
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