Discontinuous yielding in an AlLiZr alloy

Kubin, L.P.; Styczynski, A.; Estrin, Yuri

doi:10.1016/0956-716x(92)90660-7

Cited by 29 publications

(11 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Their model however suggests that since forest hardening is insignificant in precipitation strengthened alloys, plastic instability is not expected to occur in such materials unless a solute aging effect on the precipitate strengthening mechanism exists. These theoretical models [18][19][20] question the widely accepted view that DSA by Li atoms alone governs plastic instability in precipitation strengthened Al-Li based alloys [21][22][23][24][25]. The plausibility of DSA by Li to activate nSRS in Al-Li alloys is further undermined by the rather weak binding energy of Li atoms to dislocation cores [26].…”

Section: Introductionmentioning

confidence: 80%

“…The slightly higher volume fraction of d 0 phase in OA in comparison with NA, in addition to a high density of other precipitates, including Li bearing precipitates such as T 1 phase in PA and T 2 and T B phases in OA affirms this fact. In other words, if DSA by Li exclusively governs the occurrence of plastic instability in Al-Li based alloys, as suggested by several authors [21][22][23][24][25], then this phenomenon should ordinarily occur in the NA temper. Our analyses however show that this is not the case; the absence of plastic instability in the NA temper is clearly not associated with a deficiency of Li atoms.…”

Section: Dynamic Strain Agingmentioning

confidence: 92%

See 1 more Smart Citation

New insights into plastic instability in precipitation strengthened Al–Li alloys

Ovri

Lilleodden

2015

Acta Materialia

View full text Add to dashboard Cite

A mechanistic model that describes the microscopic mechanisms underlying plastic instability in precipitation strengthened Al-Li based alloy systems is proposed in this work. The model is based on experimental observations from high resolution nanoindentation tests and transmission electron microscopy (TEM) based methods, including in situ TEM tensile straining. These experiments show that dynamic strain aging (DSA), which is widely accepted as the underlying mechanism for plastic instability, cannot sufficiently account for the occurrence of plastic instability in Al-Li based alloy systems. It is proposed that an altogether different mechanism controls plastic instability, namely a diffusion-controlled pseudo-locking mechanism that accompanies order hardening. This mechanism does not require the concurrent operation of DSA by Li, which may be a nonviable mechanism given the low binding energy of Li to dislocation cores, for plastic instability to occur.

show abstract

Section: Introductionmentioning

confidence: 80%

Section: Dynamic Strain Agingmentioning

confidence: 92%

New insights into plastic instability in precipitation strengthened Al–Li alloys

Ovri

Lilleodden

2015

Acta Materialia

View full text Add to dashboard Cite

show abstract

“…Gliding dislocations are likely to meet the T 1 precipitates on 4 different {111} planes, that is, (111), (-111), (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11), and (11-1) as schematically shown in Fig. 9.…”

Section: Texture Effect On Serration In Reversiontreated Specimenmentioning

confidence: 99%

“…Explanation of serrated flow, or the Portevin-Le Chatelier (PLC) effect, in Al-Li alloys is based on two lines of thought: One is dynamic strain aging (DSA) involving dynamic interaction between dissolved lithium solute atoms and mobile dislocations [1][2][3][4] and another is shearing of d 0 (Al 3 Li) precipitates by mobile dislocations [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Texture effect on serrated flow in 2090 Al-Li alloy

Shen

Lee³

2005

Mat.-wiss. u. Werkstofftech.

View full text Add to dashboard Cite

Tensile specimens of 1Â6Â25 mm in gauge dimension were cut from the surface and centre of 12.7 mm thick 2090 Al-Li alloy plate, which were solution treated at 550 C for 30 min, peak-aged at 190 C for 18 h, or reversion-treated at 275 C for 2 min. The flow stress of the centre layer was higher than that of the surface layer, regardless of the heat treatments. The textures of the surface and centre layers were approximated by the {001}<110> and {011}<211> orientations, respectively. The solution-treated specimens gave rise to extensive serrations in their flow curves at a strain rate of 2Â10 -4 s -1. The serration amplitude was drastically reduced after the specimens were peak-aged or reversion-treated. However, for the peak-aged alloy, the surface-layer specimens underwent complex, serrated flows, whereas the flow curve of the centre-layer specimen was almost devoid of serration. The serration, especially fine-type serration in the peak-aged and reversion-treated specimens tended to disappear with increasing strain rate. The tensile behavior was explained in terms of the texture and strain rate.

show abstract

“…especially Li 30 and Cu and Mg. 31 The serrated yielding also is attributed to the rapid release of dislocations previously pinned by an atmosphere of lithium atoms (and their associated vacancies). 32 Wert and Wycliffe 33 have shown that serrated flow vanishes concurrently with precipitation of S phase in an Al-10Li-0.5Cu-0.8Mg-0.02Zr alloy.…”

Section: Precipitation and Strengtheningmentioning

confidence: 99%

Microstructure and precipitation in Al–Li–Cu–Mg–(Mn, Zr) alloys

Gao¹,

Starink²,

Davin³

et al. 2005

Materials Science and Technology

View full text Add to dashboard Cite

Hot rolled Al-6Li-1Cu-1Mg-0.2Mn (at.%) (Al-1.6Li-2.2Cu-0.9Mg-0.4Mn, wt.%) and Al-6Li-1Cu-1Mg-0.03Zr (at.%) (Al-1.6Li-2.3Cu-1Mg-0.1Zr, wt.%) alloys developed for age forming were studied by tensile testing, electron backscatter diffraction (EBSD), three-dimensional atom probe (3DAP), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). For both alloys, DSC analysis shows that ageing at 150°C leads initially to formation of zones/clusters, which are later gradually replaced by S phase. On ageing at 190°C, S phase formation is completed within 12 h. The precipitates identified by 3D atom probe and TEM can be classified into (a) Li-rich clusters containing Cu and Mg, (b) a plate-shaped metastable precipitate (similar to GPB2 zones/S''), (c) S phase and (d) δ' spherical particles rich in Li. The Zr containing alloy also contains β' (Al 3 Zr) precipitates and composite β'/δ' particles. The β' precipitates reduces recrystallisation and grain growth leading to fine grains and subgrains.

show abstract

Discontinuous yielding in an AlLiZr alloy

Cited by 29 publications

References 5 publications

New insights into plastic instability in precipitation strengthened Al–Li alloys

New insights into plastic instability in precipitation strengthened Al–Li alloys

Texture effect on serrated flow in 2090 Al-Li alloy

Microstructure and precipitation in Al–Li–Cu–Mg–(Mn, Zr) alloys

Contact Info

Product

Resources

About