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SUMMARY:Navigating the BCC-B2 Refractory Alloy space: Stability and therma
 l processing with Ru-B2 precipitates - Dr. Sebastian Kube\, Materials Depa
 rtment\, University of California\, Santa Barbara\, USA
DTSTART:20231102T151500Z
DTEND:20231102T161500Z
UID:TALK206932@talks.cam.ac.uk
CONTACT:Julie Smith
DESCRIPTION:Refractory multi-principal element alloys (RMPEAs) could provi
 de next-generation high temperature alloys\, but their ductility and high 
 temperature strength need significant improvement. Emulating superalloy γ
 -γ’ microstructures\, RMPEAs combining a ductile BCC matrix with embedd
 ed B2 precipitates for strengthening could meet this goal. Two-phase BCC-B
 2 RMPEAs have recently been demonstrated\, but the B2 phase typically exhi
 bits insufficient thermodynamic stability for operating temperatures ≥13
 00°C.\nUsing high-throughput CALPHAD predictions\, we screen across 3500 
 potential BCC-B2 systems. Promising compositions are predicted for alloys 
 combining Ru-based B2s with refractory BCC elements. A total of 20 such co
 mpositions were arc-melted to characterize their as-cast and heat-treated 
 microstructures. In these alloys\, the RuHf B2 exhibits exceptional stabil
 ity beyond 1900°C but cannot be solutionized. By contrast\, RuTi does sol
 utionize and reprecipitate between 1300 and 1900°C\, providing a robust t
 hermal processing pathway. RuAl can be solutionized but also tends to form
  competing intermetallic phases. Altogether\, Ru-B2 RMPEAs offer great des
 ign flexibility and surpass the stability and thermal processability of pr
 eviously studied BCC-B2 refractory alloys.\n
LOCATION:Goldsmiths 2 &amp\; https://zoom.us/j/96836714124
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