High-order additions to platinum-based alloys for high-temperature applications
Abstract
Platinum-based alloys are being developed with microstructures similar to nickel-based superalloys for potential high-temperature applications in aggressive environments. Since the chemistries of nickel and platinum are similar, Pt-based alloys can be made with gamma prime -Pt3Al precipitates in a gamma (Pt) matrix. Currently, the Pt-Al-Cr-Ru system is one of the bases for developing Pt-based alloys, where Al allows the formation of the Pt3Al precipitate and also gives protection from the alumina scale formed, Cr provides oxidation resistance and stabilization for the L12 -Pt3Al phase, and Ru provides solid solution strengthening in the (Pt) matrix.
Four Pt-Al-Cr-Ru-V and two Pt-Al-Cr-Ru-V-Nb alloys were made, with compositions based on a quaternary alloy, ~Pt82:Al12:Cr4:Ru2, which had previously been identified as having optimum properties. Four of the as-cast alloys had the targeted two-phase structure of ~Pt3Al and (Pt), and two were single-phase -PtjAl. Vanadium partitioned more to (Pt) than to -PtjAl. There was an improvement in hardness compared to the quaternary alloys. The best addition of V was -15 at.%; higher additions resulted in brittle intermetallic phases of the Pt-V system. The effect of Nb could not be ascertained because of its high losses.
URI
http://www.scielo.org.za/scielo.php?pid=S0038-223X2015000300012&script=sci_arttext&tlng=enhttp://hdl.handle.net/11295/86623
Citation
Odera, B. O., Papot, M. J., Couperthwaite, R., Radingt, G. O., Billing, D., & Cornish, L. A. (2015). High-order additions to platinum-based alloys for high-temperature applications. Journal of the Southern African Institute of Mining and Metallurgy, 115(3), 241-250.Publisher
University of Nairobi