Matrix Transformation in Boron Containing High-Temperature Co–Re–Cr Alloys |
| |
Authors: | Pavel Strunz Debashis Mukherji P?emysl Beran Ralph Gilles Lukas Karge Michael Hofmann Markus Hoelzel Joachim Rösler Gergely Farkas |
| |
Affiliation: | 1.Nuclear Physics Institute of the CAS,?e?,Czech Republic;2.Institut für Werkstoffe,Technische Universit?t Braunschweig,Braunschweig,Germany;3.Heinz Maier-Leibnitz Zentrum (MLZ),Technische Universit?t München,Garching,Germany;4.Department of Physics of Materials, Faculty of Mathematics and Physics,Charles University,Prague,Czech Republic |
| |
Abstract: | An addition of boron largely increases the ductility in polycrystalline high-temperature Co–Re alloys. Therefore, the effect of boron on the alloy structural characteristics is of high importance for the stability of the matrix at operational temperatures. Volume fractions of ε (hexagonal close-packed—hcp), γ (face-centered cubic—fcc) and σ (Cr2Re3 type) phases were measured at ambient and high temperatures (up to 1500 °C) for a boron-containing Co–17Re–23Cr alloy using neutron diffraction. The matrix phase undergoes an allotropic transformation from ε to γ structure at high temperatures, similar to pure cobalt and to the previously investigated, more complex Co–17Re–23Cr–1.2Ta–2.6C alloy. It was determined in this study that the transformation temperature depends on the boron content (0–1000 wt. ppm). Nevertheless, the transformation temperature did not change monotonically with the increase in the boron content but reached a minimum at approximately 200 ppm of boron. A probable reason is the interplay between the amount of boron in the matrix and the amount of σ phase, which binds hcp-stabilizing elements (Cr and Re). Moreover, borides were identified in alloys with high boron content. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|