Reactive synthesis and ultrafast sintering of refractory compositionally complex alloy-carbide composites

May 6, 2025

(a) EBSD-measured grain size vs. CCC fraction curves for the BCC RCCA NbMoTaW, subcarbide CCC (Nb0.37Mo0.11Ta0.39W0.13)2C, and monocarbide CCC phases. (b) Vickers microhardness measurements of ultrafast-sintered specimens with increasing PCA additions (Courtesy Scripta Materialia)
(a) EBSD-measured grain size vs. CCC fraction curves for the BCC RCCA NbMoTaW, subcarbide CCC (Nb0.37Mo0.11Ta0.39W0.13)2C, and monocarbide CCC phases. (b) Vickers microhardness measurements of ultrafast-sintered specimens with increasing PCA additions (Courtesy Scripta Materialia)

Researchers from the University of California San Diego, La Jolla, California, USA, have released a paper in Scripta Materialia focused on the reactive synthesis and ultrafast sintering of refractory compositionally complex alloy-carbide composites.

NbMoTaW – a refractory compositionally complex alloy (RCCA) with a well-dispersed compositionally complex carbide (CCC) reinforcing secondary phase – is made through high-energy ball milling (HEBM) and ultrafast high-temperature sintering (UHS). The study successfully demonstrated the use of ultra-fast sintering of RCCA-CCC composites to deliver high relative densities (approx. 92-95%) in around seventy seconds.

THE WORLD OF METAL POWDERS TO YOUR INBOX
Subscribe to our weekly newsletter
Register now

The researchers used stearic acid PCA as a carbon source to form a controllable fraction of well-dispersed (i.e. harder) CCC phase(s) in the metallic RCCA matrix.

The high heating and cooling rates during ultrafast sintering also enabled the formation of the favourable P3¯m1 subcarbide CCC phase (Nb0.37Mo0.11Ta0.39W0.13)2C. A thermodynamic model was proposed to explain the Nb and Ta enrichments in (Nb0.37Mo0.11Ta0.39W0.13)2C from more negative carbide formation energies for Nb2C and Ta2C. An additional rock-salt monocarbide CCC was found only in RCCA-20CCC (with the highest 1 wt% PCA addition). The well-dispersed CCC phase reduced the grain size and improved the hardness.

‘Reactive synthesis and ultrafast sintering of refractory compositionally complex alloy-carbide composites’ is available here.

www.ucsd.edu

In our latest magazine…

Download PDF

Extensive metal powder and Powder Metallurgy news coverage, plus the following exclusive deep-dive articles and reports:

  • GKN Powder Metallurgy targets sustainable and resilient regional NdFeB magnet production
  • The chemistry of LiFe: The rise of LFP batteries and what it means for the iron powder industry
  • Driving sustainable innovation: HIP 2025 explores the strategic potential of Hot Isostatic Pressing
  • High-precision press solutions for permanent magnets in EVs and green energy generation
  • Powder2Powder: A closed-loop solution for high-value metal powder recycling
  • Reducing defects and energy use in Hot Isostatic Pressing: A data-driven approach to degassing

The latest news from the world of metal powders, delivered to your inbox

Don't miss any new issue of Metal Powder Technology, and get the latest industry news. Sign up to our weekly newsletter.

Sign up

Join 5,000+ other industry professionals – follow us online

Discover our magazine archive…

The free-to-access Metal Powder Technology magazine archive offers unparalleled insight into the world of metal powder from a commercial and technological perspective through:

  • Reports on visits to leading PM part manufacturers, metal powder manufacturers and industry suppliers
  • Articles on technology and application trends
  • Information on materials developments
  • Reviews of key technical presentations from the international conference circuit
  • International industry news

All past issues are available to download as free PDFs or view in your browser.

 

Browse the archive

 

Looking for PM production equipment, metal powders, R&D support and more?

Discover suppliers of these and more in our
advertisers’ index and buyer’s guide, available in the back of Metal Powder Technology magazine.

  • Powders & materials
  • Powder process, classification & analysis
  • PM products
  • Atomisers & powder production technology
  • Compaction presses, tooling & ancillaries
  • Sintering equipment & ancillaries
  • Post-processing
  • HIP Services
  • AM Machines
  • Consulting & toll sintering
View online
Share via
Copy link