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Effect of Strain Path Reversal on Austenite Grain Subdivision and Deformation Induced Ferrite Transformation Studied by Hot Torsion

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journal of Iron and Steel Research International 2011年第S1期18卷 233-237页

作者： Muszka Krzysztof Wynne Bradley P palmiere eric j Institute for Microstructural and Mechanical Process Engineering The University of SheffieldMappin StreetSheffield S1 3JDUK

The effects of large strain and strain path reversal on the deformation microstructure evolution in austenite below the recrystallisation temperature were studied by hot torsion using a non-transforming Fe-30wt%Ni model austenitic *** show that the high angle boundaries (HABs) can be generated by both microstructure mechanism through dislocation accumulation and texture mechanism via subgrain ***,multiple strain path reversals lead to less well-developed HABs in the original grains compared to single reversal deformed to the same amount of total accumulative *** effect is attributed to the subgrain rotation mechanism being less effective at small *** comparison,the same hot torsion tests were conducted using a microalloyed steel at a temperature between Ae 3 and Ar *** single strain path reversal,substantial deformation-induced austenite-to-ferrite phase transformation was ***,a test with multiple strain path reversals but with the same total strain produces much lower levels of strain-induced ferrite *** difference is correlated to the observations made in the Fe-30wt%Ni model *** is believed that the different amount of strain-induced ferrite originated from the different levels of strain-induced HABs within the austenite which act as ferrite nucleation sites.

关键词： strain induced transformation ultra fine ferrite dislocation boundaries EBSD

Effect of Cooling Rate on the Room Temperature Microstructure Following the Intercritical Deformation of Steel S460

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journal of Iron and Steel Research International 2011年第S1期18卷 500-505页

作者： Hinton john S palmiere eric j Rainforth W.Mark IMMPETUS Dept.Of Materials Science and EngineeringThe University of SheffieldMappin StSheffieldSouth YorkshireS1 3JDUK

The effect of final hot rolling in the intercritical (α+γ) region on microstructure and properties is very specific to the individual processing conditions and the chemical composition of a steel.S460 is a plate steel processed in this *** reproduce at the laboratory scale,a multi-stage simulation was developed which included a high temperature austenite deformation and an isothermal *** effect of the applied cooling rate following intercritical deformation was *** 1K/s (typical industrial cooling) the microstructure was similar to the reference sample,but included an intragranular ferrite *** was due to differences in processing history,and considered to be linked to a larger prior austenite grain *** an accelerated cooling rate (15K/s),acicular ferrite formed on shear bands within the strained austenite *** scans have been completed to provide further information about the microstructures,with band contrast able to identify the pearlite phase at the slowest cooling *** is a starting point from which to focus on the ferrite morphologies.

关键词： intercritical deformation cooling rate laboratory simulation plate steel acicular ferrite

Microstructure Evolution as an Effect of Strain Reversal During the Hot Deformation of Microalloyed Steels

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journal of Iron and Steel Research International 2011年第S1期18卷 213-217页

作者： Muszka Krzysztof palmiere eric Majta janusz AGH University of Science and Technology Mickiewicza 3030-059 KrakowPoland IMMPETUS University of SheffieldMappin St.S1 3JD SheffieldUnited Kingdom

Susceptibility of the steel for further cold processing strongly depends on the whole prior history of deformation in the hot working *** the industrial hot working processes,*** the roughing stage of hot rolling,or forging,material undergoes complex deformation modes that leads to gradients of both microstructure and properties across the deformed *** and multiaxial compression tests with different amounts of strain reversals were conducted at elevated temperatures to study the effect of applied strain path on the phenomena occurring during microstructure evolution of Nb-microalloyed *** results will provide data for the modification of existing constitutive equations that mostly do not account for the strain path *** through-process modelling will then enable to achieve better properties and quality of the products for further cold processing.

关键词： strain reversal strain path history microstructure microalloyed steel

Cellular automata modelling of austenite grain coarsening during reheating——I. Normal grain coarsening

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journal of University of Science and Technology Beijing 2004年第6期11卷 517-523页

作者： WanhuaYU E.j.palmiere S.P.Banks jingtaoHan MaterialsScienceandEngineeringSchool UniversityofScienceandTechnologyBeijingBeijing100083China DepartmentofEngineeringMaterials UniversityofSheffieldSheffieldS13JDUK DepartmentofAutomaticControlandSystemsEngineering UniversityofSheffieldSheffieldS13JDUK

A two-dimensional cellular automaton (CA) model has been developed for thedescription of the normal grain coarsening process. The probabilistic CA method incorporatingMoore's definition of the neighbourhood is used to simulate the normal grain coarsening process witha new transition rule. The model simulates the grain coarsening process in as much detail that ispossible, from the point of initial nucleation to subsequent coarsening with computational *** unique result is that the grain coarsening speed can be controlled by the specific method, thisresult is vital to model the grain coarsening quantitatively. In order to make this model valid,experimental work has been done to provide solid evidence for this model. Comparison of themodelling result and the experimental result has been carried out.

关键词： computer simulation grain growth microstructure reheating

Cellular automata modelling of grain coarsening during reheating——Ⅱ. Abnormal grain growth

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journal of University of Science and Technology Beijing 2005年第1期12卷 26-32页

作者： WanhuaYu E.j.palmiere S.P.Banks jingtaoHan DepartmentofMaterialsEngineering UniversityofScienceandTechnologyBeijingBeijing100083China DepartmentofEngineeringMaterials UniversityofSheffieldS13JDSheffieldUK DepartmentofAutomaticControlandSystemsEngineering UniversityofSheffieldS13JDSheffieldUK

The 2-dimensional cellular automata (CA) simulation technique has been utilized to investigate the abnormal grain coarsening. The growth of abnormal grains is modelled under this assumption that different grains have different boundary energies and boundary mobilities. As temperature increases, some grains may first get rid of the particle pinning effect. Thus a high probability is obtained for atoms to jump over the boundary, so that they can consume other primary retained grains quickly. From the simulation, the characteristics of the abnormal grain coarsening under different conditions are demonstrated successfully. An experiment has also been carried out to reflect the abnormal grain coarsening on the microalloy steel. Simulation results are quite close to the experimental evidence.

关键词： computer simulation grain growth microstructure reheating

Multi-Pass Simulation of Heavy Plate Rolling Including Intermediate Forced Cooling

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journal of Iron and Steel Research International 2011年第S1期18卷 506-510页

作者： E.j.palmiere A.A.Howe H.C.Carey Institute for Microstructural and Mechanical Process Engineering:The University of Sheffield (IMMPETUS) Sir Robert Hadfield BuildingMappin StreetSheffieldS1 3JDUK Tata Steel Research Development &Technology Swinden Technology CentreMoorgateRotherham S60 3ARUK

Thermomechanical Controlled Processing (TMCP) including accelerated cooling after the final hot rolling pass is a well-established technology,widely applied in HSLA steel plate ***,there are still certain limitations,especially for thicker *** rolling schedule includes a long holding period (HP) after the roughing stage to allow the temperature to fall sufficiently for optimised TMCP during *** Forced Cooling (IFC) applied during the HP can increase productivity by decreasing the required hold time,can restrict austenite grain growth,and can also improve the subsequent strain penetration in thick plate with further metallurgical ***-pass plane strain compression (PSC) tests have been performed on the thermomechanical compression (TMC) machine at Sheffield University including different severities of *** it is impossible to simulate all aspects of the temperature and strain gradients present in thick plates in laboratory specimens,and most of the tests were conducted at temperatures and strains calculated by Finite Element modelling as relevant to specific positions through the plate ***,some aspects of the gradients were addressed with tests using cold *** results have indeed shown that IFC can shorten the HP and reduce austenite grain growth and its variation across thick plate.

关键词： Steel plate rolling intermediate forced cooling plane strain compression recrystallisation grain growth finite element modelling temperature and strain distribution

CELLULAR AUTOMATA MODELLING OF GRAIN COARSENING DURING REHEATING AND VALIDATION WITH THE EXPERIMENTAL RESULTS

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Acta Metallurgica Sinica(English Letters) 2005年第2期18卷 113-120页

作者： W.H.Yu E.j.palmiere S.P.Banks j.T.Han SchoolofMaterialsScienceandEngineering UniversityofScienceandTechnologyBeijingBeijing100083China DepartmentofEngineeringMaterials UniversityofSheffieldSheffieldS13JDUK DepartmentofAutomaticControlandSystemsEngineering UniversityofSheffieldSheffieldS13J-DUK

A novel 2D cellular automata (CA) model has been developed for description of normal grain coarsening and abnormal grain coarsening process. The program reflects the grain coarsening quite well even through the average grain size becomes very large. Follow results have been obtained: (a) The model reflect the normal grain growth kinetics gradually increase with probability and grain growth speed can be controlled. Based on this result, temperature can be coupled in the model. (b) Abnormal grain growth is modelled successfully. (c) Methodology has been put forward to find the relationship between the experiment results and modelling results. The experimental work on the grain coarsening has been carried out. Graphical output matched the realistic microstructure in every detail. Because many physical parameters can be taken into account in the CA programme, this CA model could not only qualitatively demonstrate the grain growth process, but also quantitatively predict and analyse the grain coarsening process.

关键词： computer simulation grain growth microstructure reheating

Effect of Cooling Rate on the Room Temperature Microstructure Following the Intercritical Deformation of Steel S460

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Effect of Cooling Rate on the Room Temperature Microstructur...

Gαq takes centre stage in multiple sclerosis pathogenesis

第六届国际低合金高强度钢会议

作者： Hinton john S palmiere eric j Rainforth W.Mark IMMPETUS Dept.Of Materials Science and EngineeringThe University of SheffieldMappin StSheffieldSouth YorkshireS1 3JDUK

＜正＞The effect of final hot rolling in the intercritical（α+γ） region on microstructure and properties is very specific to the individual processing conditions and the chemical composition of a steel.S460 is a plate steel processed in this *** reproduce at the laboratory scale,a multi-stage simulation was developed which included a high temperature austenite deformation and an isothermal *** effect of the applied cooling rate following intercritical deformation was *** 1 K/s（typical industrial cooling） the microstructure was similar to the reference sample,but included an intragranular ferrite *** was due to differences in processing history,and considered to be linked to a larger prior austenite grain *** an accelerated cooling rate（15K/s）,acicular ferrite formed on shear bands within the strained austenite *** scans have been completed to provide further information about the microstructures,with band contrast able to identify the pearlite phase at the slowest cooling *** is a starting point from which to focus on the ferrite morphologies.

关键词： intercritical deformation cooling rate laboratory simulation plate steel acicular ferrite

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Cellular & Molecular Immunology 2017年第5期14卷 401-402页

作者： eric j Downer School of Medicine Discipline of PhysiologyTrinity Biomedical Sciences Institute Trinity Col-lege Dublin Dublin 2 Ireland

There is no cure for multiple sclerosis （MS）; however, a number of strategies exist for disease management, including medications that reduce the frequency of relapses and long-term accrual of disability.1 However, the fact that MS therapies can be partially effective and have the risk of side effects, in addition to the observation that disability often continues to worsen despite immunotherapy, has highlighted the need for novel therapeutic targets in the disease.

关键词： Gαq centre stage multiple sclerosis