Annealing spectrum of cold-worked dilute AlLi alloys

Kamel, R.; Ali, A. R.; Farid, Z.

doi:10.1002/pssa.2210450207

Cited by 3 publications

(3 citation statements)

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“…The different recovery processes here observed in precipitating Al-10 at Ojo Li alloy were first reported by KAMEL et al [2] using internal friction and electric resistivity measurements. Accordingly, the present observed recovery processes in the temperature range 25--450 ~ might be ascribed to the growth of coherent Guinier-Preston zones formed at relatively lower temperatures [9] and the precipitation of the ~-phase (Al-Li) in the temperature range 200--300 ~ [1].…”

Section: Discussionsupporting

confidence: 67%

“…It was reported [2] that above 450 ~ Li atoms diffused to the surface of the specimen at which they ate burnt. Above 450 ~ the loss in Li concentration in the matrix seems to be responsible for the observed increase in lattice parameter and decrease in electric resistivity.…”

Section: Discussionmentioning

confidence: 99%

“…Sueh struetural ehanges affeeted largely b o t h the eleetrieal [2] and meehanieal [1] properties of the alloy.…”

Section: Introductionmentioning

confidence: 99%

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The role of lithium atoms in the structural changes in Al−Li alloy

et al. 1979

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The dependence of structural changes in preeipitating Al-10 at% Li alloy on the annealing temperatures as traeed by X-rays, eleetrie resistivity and mierohardness measurements revealed the formation and subsequent dissolution of Al-Li preeipitates in the temperature range of 25--500 ~ The observed variations were attributed to the effect of the annealing temperature on the behaviour of Li atoms within the Al matrix. The inerease of the Li concentration in the matrix due to the dissolution of Al-Li precipitates, being 3.75 at ~/o Li as obtained from X-ray measurements agreed well with the value 4.0 at % Li obtained from resistivity measurements. I n t r o d u c t i o n I t has been reported [1] t h a t in supersaturatedAl-Li alloys, the fl-phase (Al-Li) preeipitated b y annealing in the t e m p e r a t u r e range of 150--300 oC and dissolved at higher t e m p e r a t u r e s leads to the dispersion of the exeess Li atoms b y diffusion t h r o u g h the matrix. Sueh struetural ehanges affeeted largely b o t h the eleetrieal [2] and meehanieal [1] properties of the alloy.The present work airas at traeing the role of Li a t o m s in the Al m a t r i x in the struetural ehanges of different t e m p e r a t u r e s in the alloy from X -r a y diffraetion tests. Also, it is aimed at relating the variations in eleetrie resist i v i t y and mierohardness to these struetural ehanges. ExperimentalSamples of Al-10 at Yo Li were produced b y a m e t h o d previously deseribed [3]. Quenehing from 560 ~ to room t e m p e r a t u r e with a rate of 3 • 103 ~ was earried out to bring the samples in a m e t a s t a b l e s t a n d a r d eondition of solid solution. Isoehronal annealings were done b y heat pulses of 10 min at t e m p e r a t u r e s sueeessively increasing in steps of 20 ~ After eaeh heat pulse the resistanee of the samples was measured at room t e m p e r a t u r e using a standard potentiometrie m e t h o d [4]. A d u m m y sample helped to aeeount for the effeet of t e m p e r a t u r e variation. Microhardness m e a s u r e m e n t s I~ Acta Physica -,4cademiae Scientiarum Hungaricae 46, 1979

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Section: Discussionsupporting

confidence: 67%

Section: Discussionmentioning

confidence: 99%

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The role of lithium atoms in the structural changes in Al−Li alloy

et al. 1979

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On the recovery of quenched and irradiated dilute Al-Li alloys

Kamel

Ali

Farid

1978

Phys. Stat. Sol. (a)

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The annealing spectra of quenched and irradiated pure Al and dilute Al‐Li alloys containing 2.5 and 4.5 at% Li are isochronally tested in the temperature range 25 to 400 °C, by using both resistivity and internal friction measurements. The annealing spectrum of pure Al involves two recovery processes centred near room temperature and 160 °C. The first process is inferred to the coagulation of vacancies to form vacancy platelets and its subsequent collapse to give dislocation loops. The second process is attributed to the subsequent growth of the dislocation loops by dislocation climb. The annealing spectra of the quenched dilute Al‐Li alloys, shows three internal friction peaks in the temperature ranges 25 to 120, 120 to 200, and 200 to 300°C, characterized by activation energies 0.7, 1.3, and 1.44 eV, respectively. The first annealing band is ascribed to the annealing of vacancy‐Li couples formed during the quenching with the possible formation of GP zones. The second band is attributed to lithium atom dispersion. by normal diffusion from aggregates. The third annealing stage is thought to be due to the tendency of solute atoms to cluster in the matrix in the form of (AlLi) particles.

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