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Metallurgical and materials transactions / A 54(4), 1083 - 1100 (2023). doi:10.1007/s11661-022-06948-z, The martensitic transformation was studied by in situ and ex situ experiments in two high-carbon, 0.54 and 0.74 wt pct C, steels applying three different cooling rates, 15 °C/s, 5 °C/s, and 0.5 °C/s, in the temperature range around Ms, to improve the understanding of the evolution of martensite tetragonality c/a and phase fraction formed during the transformation. The combination of in situ high-energy X-ray diffraction during controlled cooling and spatially resolved tetragonality c/a determination by electron backscatter diffraction pattern matching was used to study the transformation behavior. The cooling rate and the different Ms for the steels had a clear impact on the martensitic transformation with a decrease in average tetragonality due to stronger autotempering for a decreasing cooling rate and higher Ms. A slower cooling rate also resulted in a lower fraction of martensite at room temperature, but with an increase in fraction of autotempered martensite. Additionally, a heterogeneous distribution of martensite tetragonality was observed for all cooling rates., Published by Springer, Boston

This technical report presents an overview of sample environments which are usable at the PETRA III Swedish Materials Science beamline (potentially requiring arrangement or development of the beamline layout). Alongside the description of each sample environment, illustrative materials science studies are presented that exemplify the use of these sample environments for in situ and/or in operando measurements. The sample environments are catalogued according to the research application areas, which are categorised as Thermal treatments, Electrochemistry, Catalysis, Thin films, Mechanical response of materials and Levitation. Such cataloguing means that researchers can now start their search for relevant sample environments by looking up a relevant research application area. Citations and links to specifications, published research cases and the organisation that is responsible for a given sample environment, are also provided as a basis for researchers to proceed with their research planning. QC 20230328

This inventory catalogs the software programs that have proven to be useful to the Swedish research community that conducts research at the PETRA III synchrotron, including the PETRA III Swedish Materials Science beamline. Based on publications from 2018, the inventory categorizes the various software programs used in research as either data reduction software for 2D area detector X-ray scattering images or data analysis software for WAXS, SAXS, GIWAXS, GISAXS, and PDF. Each software program has a short description of its functionality, a note of its developer, links to the original publication describing the scientific method that the software is based upon, as well as the site for downloading the software program. QC 20220902 Center for X-rays in Swedish Materials Science

The evolution of nanoscale phase separation in the ferrite phase of super duplex stainless steel 25Crsingle bond7Ni (wt%) (SDSS 2507) and two SDSS TIG (tungsten inert gas) weldments have been quantitatively investigated by small-angle neutron scattering (SANS). The results show that the phase separation is more pronounced in the SDSS weldments in comparison to the base metal SDSS 2507, especially after aging for 35,000 h at 300 °C. These results correlate with the higher ferrite micro-hardness in the aged TIG weldments than in the SDSS 2507. The enhanced phase separation is partly due to the higher contents of Cr and Ni in the ferrite of TIG weldments compared to SDSS 2507 base metal, revealed by energy-dispersive X-ray spectroscopy (EDS). Additionally, the residual strain measurements through focused ion beam and digital image correlation (FIB-DIC), indicate larger residual strains in the ferrite of weldments than in the base metal SDSS 2507. This is also believed to contribute to the enhanced phase separation.

International audience; The nanostructure of an Fe0.65Cr0.35 alloy has been investigated by atom probe tomography after highprecision thermal treatments close to the upper limit of the miscibility gap (MG). It is found that the wavelength of the decomposed ferrite between Cr-and Fe-rich regions grows exponentially when approaching the upper limit of the MG. Furthermore, the nanostructure change is gradual with temperature indicating a narrow metastable region and a diffuse transition out of the spinodal regime. Atomistic modelling near the limit of instability further supports the experimental observations. The findings are discussed in relation to the Cahn-Hilliard theory.

Population characteristics and selective migration explain around half of the previously reported superlinear urban scaling., Superlinear growth in cities has been explained as an emergent consequence of increased social interactions in dense urban environments. Using geocoded microdata from Swedish population registers, we remove population composition effects from the scaling relation of wage income to test how much of the previously reported superlinear scaling is truly attributable to increased social interconnectivity in cities. The Swedish data confirm the previously reported scaling relations on the aggregate level, but they provide better information on the micromechanisms responsible for them. We find that the standard interpretation of urban scaling is incomplete as social interactions only explain about half of the scaling parameter of wage income and that scaling relations substantively reflect differences in cities’ sociodemographic composition. Those differences are generated by selective migration of highly productive individuals into larger cities. Big cities grow through their attraction of talent from their hinterlands and the already-privileged benefit disproportionally from urban agglomeration.

International audience; Phase separation in the Fe-Cr system has been studied experimentally. The upper limit of the miscibility gap and phase separation kinetics during the early stages of decomposition was studied using Vickers micro-hardness tests and atom probe tomography. The results indicate that the upper limit of the miscibility gap in current thermodynamic descriptions is overestimated, but it is necessary to further analyze the transition across the upper limit of the miscibility gap before drawing conclusions. This work demonstrates the efficient combination of micro-hardness measurements and atom probe tomography to investigate the miscibility gap in the Fe-Cr system.

International audience

(Ti,Zr)C powder was sintered with WC-Co following an industrial process, including an isotherm at 1410 °C. A series of interrupted sintering trials was performed with the aim of studying the sintering behavior and the microstructural evolution during both solid-state and liquid-state sintering. Reference samples, using the same elemental compositions but with the starting components TiC and ZrC instead of (Ti,Zr)C, were also sintered. The microstructure was investigated using scanning electron microscopy and energy dispersive X-ray spectroscopy. It is found that the (Ti,Zr)C phase decomposes into Ti-rich and Zr-rich nano-scale lamellae before the liquid-state of the sintering initiates. The final microstructure consists of the binder and WC as well as two different γ phases, rich in either Ti (γ1) or Zr (γ2). The γ2 phase grains have a core-shell structure with a (Ti,Zr)C core following the full sintering cycle. The major differences observed in (Ti,Zr)C with respect to the reference samples after the full sintering cycle were the referred core-shell structure and the carbide grain sizes; additionally, the microstructural evolution during sintering differs. The grain size of carbides (WC, γ1, and γ2) is about 10% smaller in WC-(Ti,Zr)C-Co than WC-TiC-ZrC-Co. The shrinkage behavior and hardness of both composites are reported and discussed. QC 20170529

We outline the guiding ideas behind mechanisms-based theorizing in analytical sociology as a fruitful alternative to economics-inspired research on identification of causal effects, and discuss the potential of mechanisms-based theorizing for further development in organization and innovation studies. We discuss the realist stance on providing broader explanations as an identifying characteristic of the mechanism approach, its focus on the dynamic processes through which outcomes to be explained are brought about, and outline theoretical and methodological implications for organization and innovation studies.

under senare tid har den analytiska sociologin vuxit sig allt starkare. Artiklar och böcker om analytisk sociologi publiceras av de främsta förlagen och tidskrifterna i världen, ledande yngre forskare attraheras till området och årliga internationella konferenser anordnas. Mina egna bidrag till detta område var en viktig anledning till att jag valdes in i Akademien och i detta kapitel ska jag ge en kortfattad beskrivning av vad som karaktäriserar den analytiska sociologin. Eftersom den analytiska sociologin ägnar mycket uppmärksamhet åt hur de sociala nätverk som individer är inbäddade i påverkar olika samhällsprocesser, kommer jag även att kortfattat uppmärksamma detta.

Being an immigrant in a Swedish school today might not be easy. It´s quite difficult to be accepted and becoming a part of an already functioning group. Difficulties with the Swedish language doesn´t make it easier. Besides that the requisites of the school curriculum program are very demanding and Swedish students are often in advantage already being a part of the system for many years. By following five immigrant boys in grade 6 during ten ensemble lessons, one concert and individual interviews with the boys as well as with their teacher, this study aims to investigate how ensemble playing can function as a social tool and promote interaction as well as integration. The results in this study show that ensemble playing in fact can function as a social tool. The boys developed abilities in playing an instrument as well as cooperating and analyzing by using the social tool of ensemble playing. The results even show that ensemble playing can promote interaction as well as integration. Above everything was the concert where the boys acted in front of their classmates and were treated with great respect and acceptance.

Ponencias de WorkShop Advanced Steels 2014. Challenges in Steel Science & Technology. Celebrado en la central del CSIC, c/Serrano, 17, del 18 y 10 de septiembre de 2014.Organizado por: CENIM-CSIC, ASCO Industries (Fr), ASM Spain Chapter (Es), CTM (Es)., Advanced Steels 2014 Workshop was intended to be an open dialogue to discuss the potential and plausibility of new alloy and processing strategies that are currently being explored in the modern steel industry. In addition, fundamental investigation on advanced and complex steel structures will shed novel light on the applicability of theory, modeling and advanced techniques on the design of these kinds of materials, Comunicaciones: 1.Ulrich Prahl, Phase field modeling of bainite. 2. María Jesus Santofimia, Q&P theory. 3.Vicky Yardley, Orientation relationships and morphology in fcc-bct martensitic transformations: phenomenological theory and EBSD investigations. 4.Elisabeth Gautier, Bainite/martensite transformation under stress. 5. Cem Tasan, Multi-scale characterization of ductile martensitic stainless steels. 6. Peter Hedström, On the three-dimensional microstructure of martensite in C steels. 7. David San Martín, Sub-micrometer austenite obtained by controlled heat treatments: microstructure and mechanical properties. 8. Roumen Petrov, Advanced EBSD characterization in AHS steels. 9. José A. Jiménez, Advanced X-ray diffraction study in modern steels. 10. Juan F. Almagro Bello, Advance characterization of high-strength stainless steels. 11. Isabel Gutiérrez, Effect of microstructure of the impact toughness of HSS. 12. Daniel Casellas, Fracture toughness of high strength steels sheets: an approach to understand formability and crack edge fracture in cold forming. 13. Eberhard Kerscher, The fatigue limit of high-strength bearing steels. 14. Ilchat Sabirov, Fatigue and fracture. 15. Iñaki García, Wear behavior of HSS in discontinuous sliding contact conditions. 16. John Hald, Creep resistant martensitic/bainitic steels. 17. Pedro Rivera, Hydrogen embrittlement in complex microstructures. 18. Lars-Erik Svensson, Welding of modern bainitic/martensitic steels. 19. Sybrand van der Zwaag, Alloy design based on thermodynamics, metallurgical principles and genetic algorithms. 20. Thomas Sourmail, Air cooled bainitic steel design through tailoring of the transformation kinetics. 21. Zuriñe Idoyaga Olano, Development of new steel grades with improved mechanical properties by the addition of nanoparticles. 22. Marion Bechtold, Novel concepts for improving formability in steels for the automotive industry. 23. José Arancón, Advanced rail steels. 24. Jan Post, Multi-stage forming in stainless steels. 25. María M. Aranda, Thermodynamics and kinetics of eutectoid transformation in a Fe-C-Mn alloy: constant pearlite vs divergent pearlite.

New right-wing extremist parties all over Europe have been described as adopting a master framethat combines xenophobia and anti-political establishment populism (Rydgren 2004). In Sweden the Sweden Democrats (Sverigedemokraterna, SD) have emerged as the dominating newright-wing extremist party that was able to more than double their share of votes from the 2010 tothe 2014 parliamentary elections (2010: 5.7%, 2014: 12.9%). We conducted a vignette study in arepresentative sample of the Swedish population shortly before and after the 2014 nationalelections, which helps us to analyse the social distance between the majority population and theMuslim minority. We are explicitly taking into account the prevalence of right-wing populistattitudes in the population and their support for SD in the 2010 and 2014 elections. Our resultsshow that; (1) anti-minority attitudes (held by 36% of the population) but not anti-establishmentattitudes (held by 37% of the population) predict increased social distance to Muslims and eventowards persons that are only presented as having a foreign name, (2) SD voters hold drasticallymore negative views about Muslims than does any other voter group, (3) the vote for SD is purelydriven by anti-minority sentiments, not anti-establishmentarism. In conclusion, while SD mightpresent its cause in the language of anti-establishment populism and their voters mightlegitimise their voting choice by this principle, SD voters’ intentions are fundamentallyrooted in xenophobia. Analytical Sociology: Theoretical Developments and Empirical Research

This study investigates mechanisms of tie formation in an interorganizational network generated by the mobility of employees between organizations. We analyze a data set that contains information on all organizations in the Stockholm metropolitan area between 1990 and 2003. We show that the formation of new ties is contingent upon the direction of past ties, and that most connections occur at an intermediate geodesic distance of 2 and 3. The findings highlight the importance of tie direction and indirect connections in research on network dynamics and knowledge exchanges stemming from the mobility of employees across organizations.

This study investigates mechanisms of tie formation in an interorganizational network generated by the mobility of employees between organizations. We analyze a data set that contains information on all organizations in the Stockholm metropolitan area between 1990 and 2003. We show that the formation of new ties is contingent upon the direction of past ties, and that most connections occur at an intermediate geodesic distance of 2 and 3. The findings highlight the importance of tie direction and indirect connections in research on network dynamics and knowledge exchanges stemming from the mobility of employees across organizations.

This article focuses on agent-based computational (ABC) modeling of social interaction. It begins with an overview of ABC modeling as a computational implementation of ‘methodological individualism’, the search for the microfoundations of social life in the actions of intentional agents. It then considers how the ABC method differs from an earlier generation of modeling approaches, including game theory, equation-based models of computer simulation (such as system dynamics), and multivariate linear models. It also discusses potential weaknesses of ABC modeling and proposes research strategies to address them. The article suggests that ABC modeling will lead to significant advances in the bottom-up approach to the study of social dynamics.

The use of high-energy synchrotron x-rays which has enabled three- dimensional structural characterization from the nano- to the macroscopic scale, and now to the meso-scale, such as individual grains and dislocation structures, is a major scientific advance. This is the first technique with sufficient spatial resolution and penetration power to probe the local structure embedded deep within the material. This, together with good time resolution makes it suitable for investigations of e.g. phase transformations kinetics, stress-strain behaviour, and texture evolution in stainless steels. The micromechanical response of a metastable austenitic stainless steel and a duplex stainless steel during loading has been investigated by a series of high-energy x-ray diffraction experiments at the Advanced Photon Source (APS) in Argonne, IL, USA. Different measurement scales of the steels are tested, ranging from the behaviour of individual grains up to the macroscopic material behaviour. The experimental data is used as input to material models to validate and improve existing models for strain-induced martensite and mechanical properties. The x-ray investigations have revealed that autocatalytic Ü-martensite transformation is triggered by strains induced by the transformation itself in 301 and this was evidenced as bursts of Ü-martensite transformation during tensile loading. To the author's knowledge this behaviour has not been previously reported, and is of significant importance for the mechanical properties of the metastable stainless steels, since it provides strong local hardening and increases the time to neck formation. The å-martensite formation was investigated for 45 individual austenite bulk grains in 301 and the resolved shear stress was determined. Out of the 45 austenite grains probed one was observed to form å-martensite. The grain that formed å-martensite had the highest Schmid factor for the active slip system during fcc to hcp transformation. The behaviour of 301 during tensile loading at different strain rates was also investigated and it was concluded that even moderate strain rates produce adiabatic heating sufficient to suppress the martensite formation. The strain-induced martensitic transformation and the stress-strain behaviour was predicted by an extended Olson-Cohen model, finite element simulations for the temperature evolution and a radial return algorithm for the stress-strain behaviour. The measured and modelled results were in fair agreement. In addition, the phase specific stresses were measured during the experiments and these were in good agreement with the predicted results from the finite element model. Thus, it was concluded that the employed iso- work principle was a good assumption for the stress distribution between the phases. One way of tailoring the metastable austenitic stainless steels' microstructure with different phase fractions and deformation structures is by the reverse transformation from martensite to austenite. This was investigated for the cold rolled 301 steel, and the reverse transformation was observed to occur via two different mechanisms, one diffusion controlled and the other a diffusionless transformation. The onset of the diffusion reversion was about 450°C and the shear reversion became active at higher temperatures. The microstructure of shear reversed austenite consists of highly faulted austenite with an inherited lath like structure. The stress response of 15 individual austenite and ferrite grains deeply embedded in the bulk of a duplex stainless steel was measured during tensile loading. These results showed large intergranular stresses acting between grains due to grain interaction. The large intergranular stresses will have a significant effect on the two-phase behaviour during loading. Godkänd; 2007; 20071126 (ysko)

The strain-induced martensitic transformation in a metastable austenitic stainless steel is investigated by high-energy x-ray diffraction and material modeling. Two different deformation modes are used (cold rolling and uniaxial tensile loading) and the effect on the strain-induced martensitic transformation behavior is investigated. Moreover, three different strain rates during the uniaxial tensile loading are evaluated. The results show a sigmoidal transformation behavior of the strain-induced martensite in respect to true strain, for tensile loading. The effect of different strain rates is also clearly seen and it alters both the amount of transformed martensite and the transformation behavior. The martensite transformation is drastically decreased already at moderate strain rates such as 10-2 s-1, due to adiabatic heating of the sample. The material model used gives an accurate prediction of the strain-induced martensitic transformation behavior during tensile loading. This is valuable for further implementation of the current material model in industrial forming mulations of real components. Godkänd; 2007; 20071212 (pethed)

Residual stresses and microstructural changes during phase separation in Ti33Al67N coatings were examined using microfocused high energy x-rays from a synchrotron source. The transmission geometry allowed simultaneous acquisition of x-ray diffraction data over 360° and revealed that the decomposition at elevated temperatures occurred anisotropically, initiating preferentially along the film plane. The as-deposited compressive residual stress in the film plane first relaxed with annealing, before dramatically increasing concurrently with the initial stage of phase separation where metastable, nm-scale c-AlN platelets precipitated along the film direction. These findings were further supported from SAXS analyses. Validerad; 2006; 20070410 (ysko)

Metastable stainless steels are promising engineering materials demonstrating good corrosion resistance and mechanical properties. Their mechanical properties are however significantly affected by the deformation induced martensitic transformation. Hence, in order to use these steels to their full potential it is vital to have profound knowledge on this martensitic phase transformation. The aim of this thesis was therefore to investigate the evolution of phase fractions, texture, microstrains and microstructure to improve the current understanding of the deformation induced martensitic transformation in AISI 301. To investigate the deformation behavior of AISI 301, in-situ high-energy x- ray diffraction during tensile loading has been performed on samples suffering different cold rolling reduction. Ex-situ transmission electron microscopy, electron back-scattered diffraction and optical microscopy were also used to characterize the microstructure at different deformation levels. The results show that parts of the austenite transforms to both ά- martensite and ε-martensite during deformation of AISI 301. The transformation behavior of ά-martensite is however completely different from the transformation behavior of ε-martensite. ε-martensite forms in a parabolic behavior, while the ά-martensite transformation can be divided in three characteristic stages. The third transformation stage of ά-martensite has previously not been reported and it is characterized by a series of rapid transformations, each of which is followed by a period of yielding without any transformation. Moreover, the lattice strain evolution in the austenite at high plastic strains was found to be oscillatory, which is correlated with the stepwise transformation of ά-martensite as well as changes in x-ray peak broadening. This behavior was also coupled with the evolution of microstructure, where a distinct banded structure consisting of slip bands and Ü-martensite was observed at low plastic strains. This banded structure was however broken at high plastic strains when the ά-martensite grew larger and formed a block- shaped morphology. These findings lead to the conclusion that the three stages of ά- martensite transformation is due to different stages of nucleation and growth. The ά-martensite will first form as small nucleus, mainly at dislocation pile-ups along slip bands. The nucleuses will grow moderately in size and the structure will become saturated with nucleuses. Hence, the only way more ά-martensite can form is by growth of the existing nucleuses. This growth is very localized and seen as bursts in the transformation curve. The oscillatory behavior observed for the lattice strains during martensite formation possibly originate when semicoherent boundaries between austenite and ά-martensite become incoherent as the ά-martensite grow large. Godkänd; 2005; 20061213 (haneit)

This paper is concerned with social interactions and their importance for unemployment. A theoretical model is specified in which the social and psychological costs of unemployment depend upon the unemployment level. The theoretical analysis reveals social multiplier effects, and shows that multiple unemployment equilibria may emerge. Data on all 20- to 24-year-olds living in the Stockholm metropolitan area during the 1990s are used to test key hypotheses derived from the model. The focus is on the role of neighborhood-based reference groups, and the results support the theoretical predictions: unemployment levels vary more across neighborhood-groups than what would be expected based on variation in observable characteristics, and individuals' transition rates out of unemployment appear to be strongly influenced by the unemployment level within their neighborhood-based reference groups.

This paper is concerned with social interactions and their importance for unemployment. A theoretical model is specified in which the social and psychological costs of unemployment depend upon the unemployment level. The theoretical analysis reveals social multiplier effects, and shows that multiple unemployment equilibria may emerge. Data on all 20- to 24-year-olds living in the Stockholm metropolitan area during the 1990s are used to test key hypotheses derived from the model. The focus is on the role of neighborhood-based reference groups, and the results support the theoretical predictions: unemployment levels vary more across neighborhood-groups than what would be expected based on variation in observable characteristics, and individuals' transition rates out of unemployment appear to be strongly influenced by the unemployment level within their neighborhood-based reference groups.

QC 20191121

Coarsening of cementite (M3C) in a martensitic steel alloy Fe–1C–1Cr (wt. %) during tempering at 700 °C was investigated by electron microscopy and kinetic modelling. It is shown that the large M3C carbides are mostly located at high-angle grain boundaries in the coarsening stage and simple kinetic simulations predict the experimentally observed mean size evolution well when grain boundary diffusion of Cr is taken into account. However, the particle size distribution of M3C maintain a log-normal distribution throughout the whole extended tempering process (5000 h at 700 °C), which indicates that a modified LSW distribution , as predicted by classical steady-state coarsening theory , is not fully adequate for practical purposes in tempering of martensitic steels. QC 20180821

QC 20191121

QC 20191121