The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
F.j. Humphreys - One of the best experts on this subject based on the ideXlab platform.
-
Recrystallisation behaviour of supersaturated Al–Mn alloys Part 1 – Al–1.3 wt-%Mn
Materials Science and Technology, 2003Co-Authors: M. Somerday, F.j. HumphreysAbstract:The effects of concurrent precipitation on Recrystallisation during the isothermal annealing of a supersaturated and deformed Al – Mn alloy have been investigated. At low annealing temperatures precipitation on the prior boundaries prevents Recrystallisation whereas at high temperatures Recrystallisation is complete before precipitation occurs. In the temperature range 375 – 500°C, Recrystallisation is affected by precipitation and complex microstructures containing high fractions of low angle boundaries are formed. It is shown that strain induced boundary migration of very large boundary areas is an important Recrystallisation mechanism in this temperature range. The interactions between precipitation and Recrystallisation are analysed in terms of a simple model. The heating rate is shown to substantially affect the Recrystallisation behaviour.
-
Recrystallisation behaviour of supersaturated al mn alloys part 1 al 1 3 wt mn
Materials Science and Technology, 2003Co-Authors: M. Somerday, F.j. HumphreysAbstract:The effects of concurrent precipitation on Recrystallisation during the isothermal annealing of a supersaturated and deformed Al – Mn alloy have been investigated. At low annealing temperatures precipitation on the prior boundaries prevents Recrystallisation whereas at high temperatures Recrystallisation is complete before precipitation occurs. In the temperature range 375 – 500°C, Recrystallisation is affected by precipitation and complex microstructures containing high fractions of low angle boundaries are formed. It is shown that strain induced boundary migration of very large boundary areas is an important Recrystallisation mechanism in this temperature range. The interactions between precipitation and Recrystallisation are analysed in terms of a simple model. The heating rate is shown to substantially affect the Recrystallisation behaviour.
-
Interactions between precipitation and Recrystallisation in an Al–Mg–Si alloy
Materials Science and Technology, 2000Co-Authors: S.j. Lillywhite, Philip B. Prangnell, F.j. HumphreysAbstract:AbstractWork has been carried out to study a broad range of possible behaviours in a simple model, high-purity, ternary Al–Mg–Si alloy. The starting conditions investigated, before deformation, included a supersaturated solid solution, a very coarse β (Mg2Si)particle distribution, and a range of preaged conditions with a combination of β′ rods and β platelets, obtained by isothermal treatments at 300°C. On annealing at the same temperature of 300°C, after cold rolling to a 70% reduction, the Recrystallisation times were found to vary from 10 min to 1600 h, depending on the initial material condition. The fastest Recrystallisation time was observed with the coarse β particles, where nucleation of Recrystallisation took place rapidly by particle stimulated nucleation. In the solution treated sample, Recrystallisation took the intermediate time of 10 h and the Recrystallisation rate was found to be dominated by the transformation of the metastable β′ phase, to the equilibrium β phase at the migrating grain b...
-
Modelling mechanisms and microstructures of Recrystallisation
Materials Science and Technology, 1992Co-Authors: F.j. HumphreysAbstract:AbstractThis paper briefly reviews the various approaches, both analytical and numerical, that have been used to model the microstructural changes that occur during primary Recrystallisation. For prediction of the kinetics of Recrystallisation and the resulting grain structure, analytical methods based on the Avrami equation are still limited because of the complexity of the parameters in the equation. Numerical simulations based on a similar model show great promise, but are still not sufficiently sophisticated to accurately reproduce the grain size distributions found in practice. Monte Carlo simulations, which can successfully model grain growth after Recrystallisation, have been used to model Recrystallisation but cannot as yet be performed on a large enough scale to take into account the complexity of the deformed structure. A preliminary account is given of a new network model which aims to model Recrystallisation mechanisms by simulating subgrain boundary migration.MST/1597
M. Somerday - One of the best experts on this subject based on the ideXlab platform.
-
Recrystallisation behaviour of supersaturated Al–Mn alloys Part 1 – Al–1.3 wt-%Mn
Materials Science and Technology, 2003Co-Authors: M. Somerday, F.j. HumphreysAbstract:The effects of concurrent precipitation on Recrystallisation during the isothermal annealing of a supersaturated and deformed Al – Mn alloy have been investigated. At low annealing temperatures precipitation on the prior boundaries prevents Recrystallisation whereas at high temperatures Recrystallisation is complete before precipitation occurs. In the temperature range 375 – 500°C, Recrystallisation is affected by precipitation and complex microstructures containing high fractions of low angle boundaries are formed. It is shown that strain induced boundary migration of very large boundary areas is an important Recrystallisation mechanism in this temperature range. The interactions between precipitation and Recrystallisation are analysed in terms of a simple model. The heating rate is shown to substantially affect the Recrystallisation behaviour.
-
Recrystallisation behaviour of supersaturated al mn alloys part 1 al 1 3 wt mn
Materials Science and Technology, 2003Co-Authors: M. Somerday, F.j. HumphreysAbstract:The effects of concurrent precipitation on Recrystallisation during the isothermal annealing of a supersaturated and deformed Al – Mn alloy have been investigated. At low annealing temperatures precipitation on the prior boundaries prevents Recrystallisation whereas at high temperatures Recrystallisation is complete before precipitation occurs. In the temperature range 375 – 500°C, Recrystallisation is affected by precipitation and complex microstructures containing high fractions of low angle boundaries are formed. It is shown that strain induced boundary migration of very large boundary areas is an important Recrystallisation mechanism in this temperature range. The interactions between precipitation and Recrystallisation are analysed in terms of a simple model. The heating rate is shown to substantially affect the Recrystallisation behaviour.
B. Liao - One of the best experts on this subject based on the ideXlab platform.
-
Effect of silicon on Recrystallisation of V–Ti microalloyed steel
Materials Science and Technology, 2013Co-Authors: J. P. Pei, Y. L. Gong, W. B. Fan, F. R. Xiao, B. LiaoAbstract:The dynamic Recrystallisation (DRX) and static Recrystallisation (SRX) behaviours of three V–Ti microalloyed steels were studied by the analysis of the true stress–strain curves and the stress relaxation curves under different deformation conditions. The results of DRX showed that deformation activation energy Qdef, peak stress and peak strain increased, as a result of the solute strengthening and dragging effect due to Si. The results of SRX showed that Si increased the SRX activation energy QSRX. The solute retardation parameter for static Recrystallisation of Si was calculated. Based on the SRX results, to quantify the drag effect of Si and V, a new model was proposed to describe the time for 50% Recrystallisation (t0·5), which was tested and verified by previously published data on similar steels. Precipitation during Recrystallisation could lead to a lower value of the Avrami exponent.
O. Engler - One of the best experts on this subject based on the ideXlab platform.
-
Recrystallisation textures in copper-manganese alloys
Acta Materialia, 2001Co-Authors: O. EnglerAbstract:Manganese is the only alloying element that does not lower the (normalised) stacking fault energy (SFE) of copper-alloys. Therefore, analysis of the Recrystallisation behaviour of Cu-Mn alloys may yield information on the impact of solute atoms on the Recrystallisation, independent of the influence of the SFE. For this purpose the progress of Recrystallisation is tracked in various Cu-Mn alloys by hardness measurements and X-ray texture investigations. To support the results obtained by macrotexture analysis, and in particular to trace the origin of the Recrystallisation texture orientations, local orientation measurements are performed by means of electron back scattering diffraction (EBSD). The Recrystallisation textures as well as data on the Recrystallisation kinetics of the present Cu-Mn alloys are compared to results obtained in other binary Cu-alloys.
-
Nucleation and growth during Recrystallisation of aluminium alloys investigated by local texture analysis
Materials Science and Technology, 1996Co-Authors: O. EnglerAbstract:AbstractThis paper presents a systematic survey on the formation of Recrystallisation textures in cold rolled Al alloys. In particular, the nucleation of new grains in cube bands, grain boundaries, shear bands, and the deformation zones around large pProceedings of Conference 'Texture on a Mircoscale' as well as their subsequent growth into the deformed matrix are examined and discussed in the context of their contribution to the final Recrystallisation textures. In addition to X-ray macrotexture analysis, particular attention is focused on the determination of local orientations by electron diffraction either in the transmission electron microscope (microbeam electron diffraction) or, at later stages of Recrystallisation, in the scanning electron microscope (electron backscattered diffraction). A combination of these complementary techniques for orientation determination with increasing spatial resolution yields much more valuable information on the underlying mechanisms of Recrystallisation than is acce...
C.m. Sellars - One of the best experts on this subject based on the ideXlab platform.
-
Microstructural modelling of aluminium alloys during thermomechanical processing
Materials Science and Engineering: A, 2000Co-Authors: C.m. Sellars, Qiang ZhuAbstract:Abstract It is well-accepted that modelling of microstructural evolution of aluminium alloys during thermomechanical processing is highly desirable to predict product properties and/or to design process variables based on requirements for the properties. To do so, having soundly based physical models is of interest for both academic research and industrial practice. In the present paper, models for predicting the evolution of internal state variables such as internal dislocation density, subgrain size and misorientation between subgrains, and subsequent Recrystallisation behaviour are developed for both constant and transient deformation conditions. In predicting the evolution of the internal state variables under transient deformation conditions, the internal ‘geometrically necessary’ dislocation density is related to the subgrain boundary dislocation density. In the model to predict static Recrystallisation behaviour, nucleation of Recrystallisation is initially discussed based on experimental results and quantitative metallographic observations. In the calculation of Recrystallisation nucleation density, distribution of subgrain size and misorientation between subgrains are key parameters. The predicted evolution of internal state variables and subsequent Recrystallisation kinetics and recrystallised grain size using the developed model are in reasonable agreement with experimental data.
-
The influence of thermomechanical processing on Recrystallisation and precipitation in austenitic alloys with particular reference to the effects of deformation and ageing conditions
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 1999Co-Authors: R.t.j. Whillock, R.a. Buckley, C.m. SellarsAbstract:Abstract The Recrystallisation and precipitation behaviour of an austenitic stainless steel has been studied with particular emphasis on the role of the experimental parameters in controlling the precipitation mechanisms of sigma phase. The alloy, containing 23 wt% chromium and 23 wt% nickel and with negligible carbon (0.004 wt%), was aged isothermally at different temperatures following hot-, warm-, or cold-working. Three distinct behaviours during ageing were found: static Recrystallisation on ageing at 900°C; conventional precipitation of sigma phase after static Recrystallisation at 800°C; and ‘discontinuous Recrystallisation’ (conjoint Recrystallisation and precipitation) at 700°C and 600°C. The conditions of thermomechanical processing interacted strongly with ageing history, hot-working having least influence and cold-working the greatest significance, a consequence of the combination of the amount of strain energy available for Recrystallisation and the degree of supersaturation for sigma phase. Recrystallisation at adequate supersaturation caused discontinuous Recrystallisation, yielding very rapid and heavy precipitation, apparently approaching thermodynamic equilibrium after only a few hours of ageing. By contrast, conventional precipitation after static Recrystallisation gave only light precipitation by the same time. The distribution, shapes, and sizes of precipitates were influenced by the mechanism.
