TY - JOUR

T1 - Rapid solidification and metastable phase formation during surface modifications of composite Al-Cr cathodes exposed to cathodic arc plasma

AU - Golizadeh Najafabadi, Mehran

AU - Mendez Martin, Francisca

AU - Wurster, Stefan

AU - Mogeritsch, Johann

AU - Kharicha, Abdellah

AU - Kolozsvári, Szilárd

AU - Mitterer, Christian

AU - Franz, Robert

N1 - Publisher Copyright: © 2021

PY - 2021/12/20

Y1 - 2021/12/20

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=85107706007&partnerID=8YFLogxK

U2 - 10.1016/j.jmst.2021.03.059

DO - 10.1016/j.jmst.2021.03.059

M3 - Article

VL - 94:2021

SP - 147

EP - 163

JO - JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY

JF - JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY

SN - 1005-0302

IS - 20 December

ER -