Microstructure, Plasticity and Ductility of a TNM+ Alloy Densified by Spark Plasma Sintering

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Authors

  • Christophe Deshayes
  • Guy Molénat
  • Louise Toualbi
  • Benjamin Galy
  • Muriel Hantcherli
  • Jean-Philippe Monchoux
  • Marc Thomas
  • Alain Couret

External Organisational units

  • CEMES-CNRS
  • Université Paris-Saclay

Abstract

This work presents a study of the microstructure and mechanical properties of a TNM+ alloy (Ti-43.5Al-4Nb-1Mo-0.1B-0.3C-0.3Si, in at.%) densified by Spark Plasma Sintering (SPS), in comparison to the as-SPSed TNM alloy, which contains neither carbon nor silicon. Tensile tests at room temperature and 800 °C, as well as creep tests at 800 °C and 200 MPa, were performed. The microstructures and the fracture surfaces of deformed samples were studied by scanning and transmission electron microscopies, as well as by X-ray diffraction. The deformation mechanisms were investigated by means of in situ straining experiments and post-mortem analyses of deformed samples, both performed by transmission electron microscopy. Contrary to the TNM alloy, the as-SPSed microstructure of the TNM+ alloy does not contain β/βo phase due to the incorporation of carbon. At room temperature, the TNM+ alloy exhibits a yield stress of 520 MPa but a poor ductility of less than 0.1% of plastic strain. The incorporation of carbon and silicon leads to an increase in the creep resistance of the alloy at 800 °C. Despite the fact that iron inclusions are responsible for the premature failure of some samples during tensile tests, the TNM+ alloy is found to be able to deform plastically at room temperature by the glide of ordinary dislocations and by twinning.

Details

Original languageEnglish
Article number1915
Number of pages22
JournalMetals : open access journal
Volume12.2022
Issue number11
DOIs
Publication statusPublished - 8 Nov 2022