Rapid solidification and metastable phase formation during surface modifications of composite Al-Cr cathodes exposed to cathodic arc plasma

Mehran Golizadeh Najafabadi, Francisca Mendez Martin, Stefan Wurster, Johann Mogeritsch, Abdellah Kharicha, Szilárd Kolozsvári, Christian Mitterer, Robert Franz

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung

Abstract

A combination of both conventional and advanced high-resolution characterization techniques was applied to study the modified layers on the surface of three composite Al-Cr arc cathodes with identical nominal composition of Al-50 at.% Cr but varying powder grain sizes. The results revealed that the modified layers consist mainly of metastable phases such as Cr solid solution, high temperature cubic Al 8Cr 5, supersaturated Al solid solution, and icosahedral quasicrystal. The metastable phase formation indicates that high cooling rates were involved during the solidification of molten material produced in the arc craters during cathode spot events. The average cooling rate was estimated to be 10 6 K/s based on secondary dendrite arm spacing measurements and supporting phase-field based simulations. The formation mechanisms of the modified layers are discussed based on the obtained results and the current literature.

OriginalspracheEnglisch
Seiten (von - bis)147-163
Seitenumfang17
FachzeitschriftJOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
Jahrgang94:2021
Ausgabenummer20 December
Frühes Online-Datum18 Mai 2021
DOIs
PublikationsstatusVeröffentlicht - 20 Dez. 2021

Bibliographische Notiz

Funding Information:
The authors are grateful to Zhuo Chen and Zaoli Zhang (Austrian Academy of Sciences) as well as Boryana Rashkova (Montanuniversität Leoben, Austria) for their support with the TEM investigations. Financial support by the Österreichische Forschungsförderungsgesellschaft mbH (FFG) within the framework of the project “ArcCathodeErosion” (Project No. 856889) is highly acknowledged.

Funding Information:
The authors are grateful to Zhuo Chen and Zaoli Zhang (Austrian Academy of Sciences) as well as Boryana Rashkova (Montanuniversit?t Leoben, Austria) for their support with the TEM investigations. Financial support by the ?sterreichische Forschungsf?rderungsgesellschaft mbH (FFG) within the framework of the project ?ArcCathodeErosion? (Project No. 856889) is highly acknowledged.

Publisher Copyright:
© 2021

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