Stabilizing the L12 structure of Pt3Al(r) in the Pt-Al-Sc system

Abstract

The Pt-Al system has high potential to act as alloy base for so-called refractory superalloys. Although the envisaged strengthening phase Pt 3 Al(r) has favorable L1 2 crystal structure only at high temperatures, even small amounts of Sc stabilized L1 2 crystal structure at low temperature. Pt-Al-Sc alloys were arc melted, heat treated, and examined by means of scanning electron microscopy and X-ray diffraction (XRD). Pt 3 Al 1Ϫx Sc x (r) forms a continuous phase field from the Al-rich side to the Sc-rich side of the Pt-Al-Sc ternary system. The absolute value of the lattice misfit between cubic Pt 3 Al 1Ϫx Sc x (r) and the matrix decreases with increasing Sc content.

Platinum-Based Alloys and Coatings: Materials for the Future?

“…Compressive proof stress results indicated better properties for Pt 74.5 :Hf 17 :Rh 8.5 (at.%) than the initial ternary alloys , but the oxidation resistance was much poorer. From these beginnings, two series of Pt-based alloys were developed: Pt-Al-Cr-Ru (Douglas et al, 2009;Cornish et al, 2009b) and Pt-Al-Cr-Ni (Hüller et al, 2005;Wenderoth et al, 2005Wenderoth et al, & 2007Rudnik et al, 2008;Völkl et al, 2005Völkl et al, & 2009. Both used the advantageous properties of aluminium (with the added benefit of chromium) for forming the ~Pt 3 Al precipitates and protective alumina films.…”

“…The former used ruthenium as a solid solution strengthener, whereas the latter alloys used nickel, and avoided ruthenium because of concerns over possible room temperature formation of RuO 4 , a volatile, toxic oxide (Eagleson, 1993). The Pt-Al-Cr-Ni alloys were subjected to more rigorous mechanical testing by the researchers in Germany (Hüller et al, 2005;Wenderoth et al, 2005Wenderoth et al, & 2007Rudnik et al, 2008;Völkl et al, 2005Völkl et al, & 2009. Further work was done by researchers in South Africa on the addition of alloying elements other than ruthenium to reduce the platinum content and thereby both the expense and the mass (Shongwe et al, 2009;.…”

“…Surprisingly, the melting temperature was increased by Ni additions. The work was not continued because of the disappointingly low hardness results (Glaner & Cornish, 2003), although other research has been more encouraging (Vorberg et al, 2004Hüller et al, 2005;Völkl, et al, 2005;Wenderoth et al, 2005Wenderoth et al, & 2006.…”

“…Currently, there are three major ranges of Pt-based alloys which have been developed. One is based on Pt-Al-Cr-Ni (Hüller et al, 2005;Wenderoth et al, 2005Wenderoth et al, & 2007Rudnik et al, 2008;Völkl et al, 2005Völkl et al, & 2009, and two are based on Pt-Al-Cr-Ru (Cornish et al, 2009a;2009b;Douglas et al, 2009). Of the latter range, one is more malleable but less resistant to extreme chemical environments, whereas the other has greater chemical resistance, but is more difficult to form.…”

Структурные фазовые превращения при твердофазной реакции в тонких двухслойных пленках Al/Pt

“…Интерметал-лические соединения Al−Pt применяются в микроэлек-тронных устройствах [4,5], обладают эффектом памяти формы [6], могут использоваться в качестве огнеупор-ных сплавов [7,8] и в конструкциях солнечных элемен-тов [9].…”