Loss in coherency and coarsening behavior of Al3Sc precipitates

Iwamura, Shingo; Miura, Yoshio

doi:10.1016/j.actamat.2003.09.042

Cited by 256 publications

(95 citation statements)

References 18 publications

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“…The precipitates often exhibited the characteristic coffee-bean contrast (examples are encircled in Figs.3b and d) thus indicating the presence of coherent strain. This observation agrees well with literature data predicting the preservation of the coherent relationship till the particle size of 116 nm [2] or 40 nm [11].…”

supporting

confidence: 83%

Friction Stir Welding of an Al-Mg-Sc-Zr Alloy with Ultra-Fined Grained Structure

Malopheyev

Mironov

Kulitskiy

et al. 2014

MSF

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Effect of friction stir welding (FSW) on mechanical properties and microstructure of Al-5.4Mg-0.2Sc-0.1Zr sheets with ultra-fined grained (UFG) structure was studied. The UFG-sheets were produced by equal-channel angular pressing (ECAP) followed either by cold or hot rolling. FSW was found to be very effective for retaining the UFG microstructure as well as constituent coherent nano-scale dispersoids in the welded material. Despite the preservation effect, however, the essential material softening was observed in the weld zone. This was attributed to the recrystallization occurring during FSW. The joint efficiency for yield strength of the obtained friction stir welds was found to be 81% in the hot rolled condition and only 55% in the cold rolled state. The relatively low joint efficiency was associated with the recrystallization softening as well as with the formation of a specific "kissing bond" defect in the stir zone. The joint efficiency is believed may be improved by adjusting of welding conditions and/or tool design.

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supporting

confidence: 83%

Friction Stir Welding of an Al-Mg-Sc-Zr Alloy with Ultra-Fined Grained Structure

Malopheyev

Mironov

Kulitskiy

et al. 2014

MSF

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“…11,18,28,29) These Al 3 Sc particles are initially coherent with the surrounding matrix and have been observed to lose coherency through the detection of interfacial dislocations 11,18) upon growing to a radius between 20-40 nm. Since it was extremely difficult to observe directly the large number of fine particles produced during ageing due to the high dislocation density in the microstructure, 13) the particle growth kinetics in Al-Sc can be estimated using various relationships.…”

Section: Kinetics Of Grain Growth In Severely Strainedmentioning

confidence: 99%

“…Figure 11 shows eq. (1) plotted for various temperatures and compared with the recent experimental data of Iwamura and Miura 18) for a coarse grained Al-0.2%Sc alloy. There is good agreement between the model and experiment which indicates that eq.…”

Section: Misorientation (° )mentioning

confidence: 99%

“…Such a particle radius is below the critical range where full coherency is expected to be lost. 11,18) Therefore, the majority of particles present in Al-0.2Sc during annealing at temperatures up to 500 C are expected to remain, at least, semi-coherent.…”

Section: )mentioning

confidence: 99%

“…Coherent particles were characterised by the presence of mushroom-shaped strain fields as a result of the anisotropy in their coherency. 18) Figure 8 shows a large number of nanosized Al 3 Sc particles within a grain, whereby full coherency is denoted by the strain fields, and some larger, particles present on grain boundaries. At the highest annealing temperature (i.e.…”

Section: )mentioning

confidence: 99%

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Grain Growth in a Nanocrystalline Al-Sc Alloy

Hamilton

Ferry

2004

Mater. Trans.

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A sub-micron grained microstructure in an Al-0.2 mass% Sc alloy was produced by high strain deformation using Equal Channel Angular Pressing (ECAP). The alloy was solution treated prior to deformation, deformed by ECAP then aged at low temperature to produce a sub-micron grained microstructure with a large fraction of high angle grain boundaries (HAGB) decorated with fine Al 3 Sc particles. General grain stability and particle/grain boundary interactions were studied using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), focussed ion beam (FIB) microscopy and transmission electron microscopy (TEM). The fine-grained microstructure was found to be highly stable during annealing at temperatures up to 500 C due to Zener pinning from stable Al 3 Sc particles. The volume fraction, f , and average radius, r, of particles and their rate of coarsening were found to have a strong influence on grain growth. It was found that the limiting grain size, R c , in the Al-Sc alloy may reasonably be predicted by the relation: R c ¼ 0:17r=f . This relation is known to be applicable for coarse-grained alloys (>1 mm) and indicates its validity for predicting the limiting grain size in sub-micron, particle-containing alloys.

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