First experimental synthesis of icosahedral quasicrystals and their natural origin in a meteorite by impact processes

database, nuove specie, discrediti,
ridefinizioni, classificazioni, ecc.
Rispondi
Avatar utente
Marco E. Ciriotti
Messaggi: 25818
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

First experimental synthesis of icosahedral quasicrystals and their natural origin in a meteorite by impact processes

Messaggio da Marco E. Ciriotti » mar 28 mag, 2019 10:08

Referenza:
▪ Asimow, P., Hu, J., Ma, C., Bindi, L. (2019): First experimental synthesis of Al62Cu31Fe7 icosahedral quasicrystals and their natural origin in a meteorite by impact processes. Bulletin of the American Physical Society, 21st Biennial Conference of the APS Topical Group on Shock Compression of Condensed Matter Sunday–Friday, June 16–21, 2019; Portland, Oregon Session V1: Poster Session II, Abstract: V1.00016.

Abstract:
Quasicrystals (QCs) produced by shock recovery experiments shine light on the impact origin of natural QCs in the Khatyrka meteorite. Al62Cu31Fe7 i-phase II is a newly found natural QC that has not previously been synthesized in the laboratory. The compositions of Al-Cu-Fe QCs synthesized by shock have so far been similar but not identical to natural icosahedrite (Al63Cu24Fe13) and i-Al62Cu31Fe7. Here we present the results of a new shock recovery experiment using a compositionally graded Al-Cu-W wedge in a SS304 chamber. Surprisingly, the Al-rich region did not produce QCs whereas the intermediate Al-Cu mixture reacted with the steel chamber to generate i-Al62Cu30Fe7Cr1, co-existing with Al2Cu (khatyrkite) and Al3Cu2 (stolperite) alloys. Conceivably, this results from the effects of shear flow during shock that stabilizes the new composition of icosahedral QC. More importantly, the synthesized i-phase II is a near-exact compositional, textural and assemblage match to its natural occurrence in the Khatyrka meteorite.
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

Rispondi

Chi c’è in linea

Visitano il forum: Google [Bot] e 4 ospiti