Boundary Mobilities during Recovery and Recrystallization of Binary Al - Mn Alloys

This paper described new characterization methods and data to quantify the influence of solute atoms on grain boundary and sub-grain boundary mobilities in Al-Mn alloys with a view to their integration into recovery and recrystallization modelling. Detailed SEM measurements of grain boundary mobilities during recrystallization have been made by in-situ annealing experiments on cold deformed Al – 0.1 and 0.3wt.% Mn binary alloys. Stored energies are estimated from the sub-grain sizes and misorientations and the boundary velocities directly measured in the temperature range 200-450°C. It is shown that in many cases good agreement with the Cahn, Lücke, Stüwe model for solute drag is obtained, e.g. the activation energies are intermediate between those of boundary and volume solute diffusion. Some particular cases of rapid growth occur in Al-0.1%Mn indicating boundary breakaway from solute clouds. A complementary study of sub-grain boundary mobilities has started on the same alloys; in this case the average mobilities are estimated from FEG-SEM growth data for the average sub-grain size for temperatures in the range 150-300°C. The results are compared with some previous data on Al-Si and show similar rates.

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In-Situ Investigation of Grain Boundary Mobility and Character in Aluminum Alloys in the Presence of a Stored Energy Driving Force

MRS Proceedings ◽

10.1557/proc-819-n6.5 ◽

2004 ◽

Vol 819 ◽

Cited By ~ 3

Author(s):

Mitra L. Taheri ◽

Anthony D. Rollett ◽

Hasso Weiland

Keyword(s):

Grain Boundary ◽

Solute Drag ◽

Stored Energy ◽

Solute Content ◽

Grain Boundary Mobility ◽

Grain Boundary Character ◽

In Situ Investigation ◽

Recent Developments ◽

Annealing Experiments

AbstractThis paper investigates the effect of solute in Al alloys on grain boundary character and mobility based on experiments in which individual boundaries migrate under a stored energy driving pressure acquired from prior plastic strain; among those studied are Zr, Fe and Si. A compensation effect is noted for both alloys studied with respect to both temperature and solute content. As supported by the literature, boundaries exhibit a maximum mobility for a 38-39°<111> misorientation in initial annealing experiments; this mobility maximum is asymmetric with a sharp cutoff below 38-39° but a more gradual decrease at misorientations beyond 40°. The presence of a minimum at 38-39° is found at both higher temperatures and higher solute concentrations. A shift in texture dependency with solute and temperature is also observed. This transition from a local mobility maximum to a minimum is discussed within the context of recent developments in solute drag theory.

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Morphological Evolution of a Fully Faceted Grain Boundary

MRS Proceedings ◽

10.1557/proc-652-y3.4 ◽

2000 ◽

Vol 652 ◽

Cited By ~ 1

Author(s):

D.L. Medlin ◽

G. Lucadamo

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Grain Boundary ◽

Morphological Evolution ◽

Gold Films ◽

Complex Behavior ◽

Fine Scale ◽

Transmission Electron ◽

Annealing Experiments

ABSTRACTWe examine the morphological evolution of faceted grain boundaries in gold during annealing. Experiments were performed on <111> oriented gold films composed of two Σ=3 related orientation variants. The boundaries between these variants initially possess a high density of finely spaced (<25 nm) facets on {112} type planes. During annealing a large proportion of these fine-scale corrugations are annihilated, and the facet distribution coarsens significantly. Through in situ transmission electron microscopy (TEM), we directly observe this coarsening process. These results show a more complex behavior than geometric models for facet evolution would suggest and point to the need for an improved understanding of facet-junction properties and the interactions between grain boundary facets and dislocations.

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High Angle Grain Boundary Mobilities in a High Purity Single-Phase Al-0.1 wt% Mn Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.467-470.771 ◽

2004 ◽

Vol 467-470 ◽

pp. 771-776 ◽

Cited By ~ 3

Author(s):

Arnaud Lens ◽

Claire Maurice ◽

Julian H. Driver

Keyword(s):

Grain Boundary ◽

High Purity ◽

Subgrain Size ◽

Boundary Migration ◽

Solute Drag ◽

High Angle ◽

Migration Rates ◽

Diffusion Rates ◽

Kinetics Of

The migration rates (V) of “random” high angle grain boundaries (HAGB) during annealing of a cold deformed (e=1.3) high purity Al-0.1wt% Mn alloy were determined using a combination of in-situ annealing and EBSD in the SEM at temperatures between 200 and 330°C. The SEM heating stage used for these experiments is described and results on the local recrystallization kinetics of the Al-Mn alloy are presented. For this, the local stored energies (P) were determined by subgrain size and misorientation analyses to give the boundary mobilities (M) through the standard V = M.P equation. The solute drag “force” was analysed with the atomistic model of Lücke and Stüwe (1971) for a “loaded” boundary and used to estimate the diffusion rates in the above temperature range. The activation energies for boundary migration were found to be consistent with those of solute atoms moving behind the grain boundary, i.e. intermediate between the values for bulk and boundary diffusion of Mn.

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In-Situ Electron Microscopy Studies of the Effect of Solute Segregation on Grain Boundary Anisotropy and Mobility in an Al-Zr Alloy

MRS Proceedings ◽

10.1557/proc-839-p7.7 ◽

2004 ◽

Vol 839 ◽

Author(s):

Mitra L. Taheri ◽

Eric Stach ◽

Velimir Radmilovic ◽

Hasso Weiland ◽

Anthony D. Rollett

Keyword(s):

Electron Microscopy ◽

Grain Boundary ◽

Compensation Effect ◽

Electron Backscatter Diffraction ◽

Solute Drag ◽

Solute Segregation ◽

In Situ Tem ◽

Grain Boundary Mobility ◽

Scanning Transmission

ABSTRACTThe presence of impurities in aluminum alloys is of great interest with respect to microstructural properties, specifically, the effect of solute on texture and anisotropy. This paper presents new evidence of the pronounced effect of solute drag based on in-situ annealing and Electron Backscatter Diffraction experiments of Zr-rich Al alloys subject to prior strain. A compensation effect was found for grain boundary mobility maxima for specific boundary types. Trends in activation energy as a function of boundary type support the observations of a compensation effect with respect to temperature. Evidence for irregular motion of boundaries from in-situ observations is discussed in reference to new theoretical results that suggest that boundaries migrating in the presence of solutes should move sporadically provided that the length scale at which observations are made is small enough. A study of both boundary motion and solute segregation to specific boundary types using Scanning Transmission Electron Microscopy and in-situ TEM is presented.

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Grain boundary mobilities during recrystallization of Al–Mn alloys as measured by in situ annealing experiments

Materials Science and Engineering A ◽

10.1016/j.msea.2005.05.010 ◽

2005 ◽

Vol 403 (1-2) ◽

pp. 144-153 ◽

Cited By ~ 51

Author(s):

A. Lens ◽

C. Maurice ◽

J.H. Driver

Keyword(s):

Grain Boundary ◽

Annealing Experiments

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Tailoring the Microstructure of a Metal-Reinforced Ceramic Matrix Composite

Journal of Engineering Materials and Technology ◽

10.1115/1.482810 ◽

2000 ◽

Vol 122 (3) ◽

pp. 363-367 ◽

Cited By ~ 9

Author(s):

O. Sbaizero ◽

G. Pezzotti

Keyword(s):

Crack Propagation ◽

Ceramic Matrix Composite ◽

Spectroscopic Technique ◽

In Situ Raman Spectroscopy ◽

Stable Crack Propagation ◽

Grain Sizes ◽

In Situ Raman ◽

Bridging Stresses ◽

Good Agreement

Alumina matrix was prepared with varying amounts of metal molybdenum particles of two different grain sizes. R-curves were determined during stable crack propagation and a piezo-spectroscopic technique was used to assess the bridging stresses developed along the crack wake (at the metal/matrix interface) at the critical condition for crack propagation. In both kinds of composites, the toughness monotonically increases with the amount of molybdenum added. In addition, bridging stress and therefore toughness were higher when coarser particles were present. The theoretical R-curves calculated from the discrete (microscopic) bridging stress distribution obtained by in situ Raman spectroscopy were in good agreement with the experimental data. [S0094-4289(00)02003-X]

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In-Situ Quantification of Solute Effects on Grain Boundary Mobility and Character in Aluminum Alloys during Recrystallization

Materials Science Forum ◽

10.4028/www.scientific.net/msf.467-470.997 ◽

2004 ◽

Vol 467-470 ◽

pp. 997-1002 ◽

Cited By ~ 15

Author(s):

Mitra L. Taheri ◽

Anthony D. Rollett ◽

Hasso Weiland

Keyword(s):

Aluminum Alloys ◽

Grain Boundary ◽

Solute Drag ◽

Second Phase ◽

Boundary Mobility ◽

Grain Boundary Mobility ◽

Second Phase Particles ◽

Grain Boundary Motion ◽

New Evidence

Aluminum alloys exhibit recrystallization kinetics that vary strongly with composition. The conventional understanding is that certain alloying elements, e.g. chromium, retard grain boundary motion due to the formation of fine dispersions of second phase particles, giving rise to particle drag of boundaries. There is countervailing evidence, however, that suggests that solute drag provides a stronger influence on grain boundary mobility. This paper presents new evidence for a pronounced effect of solute based on experiments in which individual boundaries migrate under the driving pressure of stored energy from prior plastic strain. As supported by the literature, boundaries exhibit a maximum mobility for a 38-39 degree <111> misorientation in initial annealing experiments. Specifically, this mobility maximum is asymmetric with a sharp cutoff below 38-39 degrees but a more gradual decrease at misorientations beyond 40 degrees. The occurrence of other, smaller mobility peaks is discussed within the context of the sharpening of evolving maxima with discussed within the context of the sharpening of evolving maxima with increased recrystallization. The presence of a minimum at 38-39 degrees is found at both higher temperatures and higher solute concentrations. This transition from a local mobility maximum to a minimum is discussed within the context of recent theories solute drag activity.

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Atomic Layer Deposition of LiF and Lithium Ion Conducting (AlF3)(LiF)x Alloys Using Trimethylaluminum, Lithium Hexamethyldisilazide and Hydrogen Fluoride

10.26434/chemrxiv.5459653 ◽

2017 ◽

Author(s):

Younghee Lee ◽

Daniela M. Piper ◽

Andrew S. Cavanagh ◽

Matthias J. Young ◽

Se-Hee Lee ◽

...

Keyword(s):

Lithium Ion ◽

Atomic Layer ◽

Mass Gain ◽

Alloy Film ◽

Ex Situ ◽

X Ray ◽

Layer Deposition ◽

Ion Conducting ◽

Good Agreement

<div>Atomic layer deposition (ALD) of LiF and lithium ion conducting (AlF3)(LiF)x alloys was developed using trimethylaluminum, lithium hexamethyldisilazide (LiHMDS) and hydrogen fluoride derived from HF-pyridine solution. ALD of LiF was studied using in situ quartz crystal microbalance (QCM) and in situ quadrupole mass spectrometer (QMS) at reaction temperatures between 125°C and 250°C. A mass gain per cycle of 12 ng/(cm2 cycle) was obtained from QCM measurements at 150°C and decreased at higher temperatures. QMS detected FSi(CH3)3 as a reaction byproduct instead of HMDS at 150°C. LiF ALD showed self-limiting behavior. Ex situ measurements using X-ray reflectivity (XRR) and spectroscopic ellipsometry (SE) showed a growth rate of 0.5-0.6 Å/cycle, in good agreement with the in situ QCM measurements.</div><div>ALD of lithium ion conducting (AlF3)(LiF)x alloys was also demonstrated using in situ QCM and in situ QMS at reaction temperatures at 150°C A mass gain per sequence of 22 ng/(cm2 cycle) was obtained from QCM measurements at 150°C. Ex situ measurements using XRR and SE showed a linear growth rate of 0.9 Å/sequence, in good agreement with the in situ QCM measurements. Stoichiometry between AlF3 and LiF by QCM experiment was calculated to 1:2.8. XPS showed LiF film consist of lithium and fluorine. XPS also showed (AlF3)(LiF)x alloy consists of aluminum, lithium and fluorine. Carbon, oxygen, and nitrogen impurities were both below the detection limit of XPS. Grazing incidence X-ray diffraction (GIXRD) observed that LiF and (AlF3)(LiF)x alloy film have crystalline structures. Inductively coupled plasma mass spectrometry (ICP-MS) and ionic chromatography revealed atomic ratio of Li:F=1:1.1 and Al:Li:F=1:2.7: 5.4 for (AlF3)(LiF)x alloy film. These atomic ratios were consistent with the calculation from QCM experiments. Finally, lithium ion conductivity (AlF3)(LiF)x alloy film was measured as σ = 7.5 × 10-6 S/cm.</div>

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