High Temperature Alloys from Nb-Cr-Si System with Minor Additions

Abstract:

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Several Nb based alloys (Nb-20Mo-15Si-25Cr, Nb-20Mo-15Si-25Cr-5B, Nb-20Si-20Cr-5Al, and Nb-20Cr-20Si-5Hf) have been prepared to evaluate the oxidation resistance from 700 to 1400°C in air. The phase identification was determined by calculating the isothermal sections in this temperature range using PANDATTM software. The experiments involve static heating for 24 hours (short term oxidation, STO) or 7 cycles of 24 hour heating (long term oxidation, LTO). Weight gain per unit area as a function of either temperature (STO) or time (LTO) has been used to determine their oxidation resistance. However, SEM, EDS on SEM, x-ray mapping, and XRD have been used to evaluate the oxide scale characterization and the influence of various microconstituent effects have been determined. It appears that B addition may be beneficial while Al is advantageous in comparison to Hf addition. The problem of pesting, typically, in a range of temperature from 900 to 1100°C needs to be controlled through minor additions since the alloys exhibit fairly good resistance at lower and higher temperatures up to 1400°C.

Info:

Periodical:

Materials Science Forum (Volumes 654-656)

Main Theme:

Edited by:

Jian-Feng Nie and Allan Morton

Pages:

570-573

DOI:

10.4028/www.scientific.net/MSF.654-656.570

Citation:

B. Portillio et al., "High Temperature Alloys from Nb-Cr-Si System with Minor Additions", Materials Science Forum, Vols. 654-656, pp. 570-573, 2010

Online since:

June 2010

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Price:

$35.00

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