|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Refractory Metals 2016
||High Temperature Properties of Directionally Solidified Nb-rich Nb-Si-Cr Eutectics
||Florian Gang, Martin Heilmaier
|On-Site Speaker (Planned)
Niobium silicide based alloys are promising materials to replace Ni-based superalloys in high temperature structural applications. Unfortunately, good mechanical strength and oxidation resistance at elevated temperatures are difficult to be achieved simultaneously.
This challenge may be met by directional solidification (DS) of eutectic alloy compositions. It is well known that DS processing, especially of eutectic alloys, can lead to enhanced creep lifetimes, whereas the oxidation resistance may be improved by the fine-lamellar phase distribution.
For this reason, eutectic compositions of the ternary system Nb-Si-Cr are directionally solidified employing a vertical float zone process. The influence of varying processing parameters on the resulting microstructures is assessed. Compressive creep tests in vacuo under constant stress at temperatures up to 1300 °C give insights into acting creep deformation mechanisms and demonstrate the potential of DS by comparison with arc-melted samples. Likewise, reasons for the improvement of the oxidation resistance will be discussed.
||Planned: A print-only volume