| 1. |
- Palumbo, M., et al.
(författare)
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Thermodynamic modelling of crystalline unary phases
- 2014
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Ingår i: Physica status solidi. B, Basic research. - : Wiley. - 0370-1972 .- 1521-3951. ; 251:1, s. 14-32
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Tidskriftsartikel (refereegranskat)abstract
- Progress in materials science through thermodynamic modelling may rest crucially on access to a database, such as that developed by Scientific Group Thermodata Europe (SGTE) around 1990. It gives the Gibbs energy G(T) of the elements in the form of series as a function of temperature, i.e. essentially a curve fitting to experimental data. In the light of progress in theoretical understanding and first-principles calculation methods, the possibility for an improved database description of the thermodynamics of the elements has become evident. It is the purpose of this paper to provide a framework for such work. Lattice vibrations, which usually give the major contribution to G(T), are treated in some detail with a discussion of neutron scattering studies of anharmonicity in aluminium, first-principles calculations including ab initio molecular dynamics (AIMD), and the strength and weakness of analytic model representations of data. Similarly, electronic contributions to G(T) are treated on the basis of the density of states N(E) for metals, with emphasis on effects at high T. Further, we consider G(T) below 300K, which is not covered by SGTE. Other parts in the paper discuss metastable and dynamically unstable lattices, G(T) in the region of superheated solids and the requirement on a database in the calculation of phase diagrams.
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| 2. |
- Hallstedt, B., et al.
(författare)
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PrecHiMn-4—A thermodynamic database for high-Mn steels
- 2017
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Ingår i: Calphad. - : Elsevier. - 0364-5916 .- 1873-2984. ; 56, s. 49-57
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Tidskriftsartikel (refereegranskat)abstract
- This paper concerns a Calphad database that was developed to describe precipitation of cubic carbides and nitrides (V, Nb and Ti) in high manganese steels and to describe phase equilibria in high manganese steels with high aluminium content. The database has also been shown to be useful for calculations on medium manganese steels and low-density steels with varying aluminium additions. Thus the database covers a significant fraction of the steels that are termed advanced high strength steels (AHSS) of the second and third generation. A number of systems were assessed (or reassessed) for the database, namely Fe–Mn–Al, Fe–Mn–C, Fe–Nb, Mn–Nb, Fe–Mn–Nb, Fe–Nb–V, Fe–Nb–C, Mn–Nb–C, Fe–Mn–Nb–C, Nb–N, Fe–Mn–Nb–N. The remaining systems were taken from published assessments. The database covers the elements Fe, Mn, Al, Si, V, Nb, Ti, C and N.
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| 3. |
- Gebhardt, T., et al.
(författare)
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Ab initio lattice stability of fcc and hcp Fe-Mn random alloys
- 2010
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Ingår i: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 22:29, s. 295402-
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the lattice stability of face centred cubic (fcc) versus hexagonal close packed (hcp) Fe-Mn random alloys using ab initio calculations. In the calculations we considered the antiferromagnetic order of local moments, which for fcc alloys models the magnetic configuration of this phase at room temperature (below its Neel temperature) as well as their complete disorder, corresponding to paramagnetic fcc and hcp alloys. For both cases, the results are consistent with our thermodynamic calculations, obtained within the Calphad approach. For the room temperature magnetic configuration, the cross-over of the total energies of the hcp phase and the fcc phase of Fe-Mn alloys is at the expected Mn content, whereas for the magnetic configuration above the fcc Neel temperature, the hcp lattice is more stable within the whole composition range studied. The increase of the total energy difference between hcp and antiferromagnetic fcc due to additions of Mn as well as the stabilizing effect of antiferromagnetic ordering on the fcc phase are well displayed. These results are of relevance for understanding the deformation mechanisms of these random alloys.
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| 4. |
- Isaksson, Ola, 1969, et al.
(författare)
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Perspectives on innovation: The role of engineering design
- 2019
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Ingår i: Proceedings of the International Conference on Engineering Design, ICED. - : Cambridge University Press (CUP). - 2220-4334 .- 2220-4342. ; 2019-August, s. 1235-1244
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Konferensbidrag (refereegranskat)abstract
- The aim of the paper is to foster a discussion in the engineering design community about its understanding of the innovation phenomena and the unique contribution that comes from engineering design. The paper reports on the dialouge originating from a series of workshops with participants from different backgrounds in engineering design, systems engineering, industrial design psychology and business. Definitions of innovation are revisited as used in business, management and engineering design contexts. The role of innovation is then discussed related to product development from (i) the management perspective, (ii) a systems architecture perspective and (iii) in relation to sustainable development as one driver of innovation. It is argued that engineering design has a central role in how to realise the novelty aspect of innovation and often plays a critical role in maturing these into the valuable products, and there is a need to articulate the role of engineering design in innovation to better resonate with the business and management research.
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| 5. |
- Zuazo, I., et al.
(författare)
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Low-Density Steels : Complex Metallurgy for Automotive Applications
- 2014
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Ingår i: JOM. - : Springer Science and Business Media LLC. - 1047-4838 .- 1543-1851. ; 66:9, s. 1747-1758
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Tidskriftsartikel (refereegranskat)abstract
- The current aim in the development of third-generation steels for lightweighting automotive applications is to increase strength keeping at least the same formability as current steel concepts. In this philosophy, an optimal concept would be one that brings, in addition, a lower density. For this purpose, low-density steels have been designed with important aluminum additions obtaining density reductions of 8-10% or higher in comparison with low-carbon steels. At the levels required for lightweighting, aluminum introduces complex phenomena in steels. Here, some of the effects of aluminum in phase stability, CALPHAD-type modeling, and microstructure development are described, the latter in relation with mechanical properties. Finally, the potential of two families of lightweight steels for automotive applications is assessed by comparison with a steel currently present in automotive structures.
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