Optimization of the Mo-Cr binary system for Nanophase Separation Sintering

Christian Oliver, Christopher A. Schuh*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Like many refractory metals, molybdenum-based alloys present a host of desirable properties for high temperature applications, but have challenging processing constraints. Nanophase separation sintering (NPSS) is a novel sintering process that has been shown to promote rapid pressureless sintering in other BCC metals such as W and Cr. These unique traits are achieved through the development of a transient secondary solid phase neck that first forms and then resolutionizes during the sintering cycle. Both of these processes promote extra mass transport and therefore accelerate sintering to from a dense material. In the present work we use the design criteria for NPSS to identify Cr as a preferred NPSS sintering aid candidate for Mo, a base metal not previously sintered by NPSS. Constant heating rate sintering experiments and ex-situ SEM and EDS on Mo-Cr alloys confirm that the critical mechanisms associated with NPSS occur in this system. Further experiments explore the effect of lower temperature isothermal holds and sintering aid content on the densification of the material. Cr is a particularly desirable sintering aid because it is fully soluble, leaving no permanent second phase or promoting rapid grain growth, which might compromise the high temperature properties of a Mo-based alloy.

Original languageEnglish (US)
Article number101410
JournalMaterialia
Volume22
DOIs
StatePublished - May 2022

Keywords

  • Kinetic analysis
  • Molybdenum
  • Nanocrystalline
  • Phase separation
  • Sintering

ASJC Scopus subject areas

  • General Materials Science

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