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Mechanical properties of Co3Ti polycrystals alloyed with various additions
- Source :
- Journal of Materials Science; December 1989, Vol. 24 Issue: 12 p4458-4466, 9p
- Publication Year :
- 1989
-
Abstract
- Third elements including vanadium, tantalum, chromium, molybdenum, tungsten, iron, nickel, aluminium and germanium, were added to L1<subscript>2</subscript>-type Co<subscript>3</subscript>Ti polycrystals with a composition of 23 at % Ti. Tensile tests from 77 to 1273 K were carried out to investigate the mechanical properties of these alloys. Anomalous increases of the yield stress with increasing temperature were observed from 473 to 973 K (or 1100 K depending on the strain rates) for all tested alloys. It was also observed that the yield stress increased with decreasing temperature below 473 K and decreased with increasing temperature above 973 K (or 1100 K). The yield stresses above the peak temperature were very sensitive to the strain rate and grain size. Microstructural observation showed that gram-boundary sliding had a considerable contribution to the fall in yield stress at high temperatures. The elongation showed a maximum around 673 K and a minimum around 1073 K for all alloys. Microstructural and fractographic observation showed that most alloys tested suffered from hydrogen-related embrittlement at ambient temperatures and grain-boundary cavitation-related embrittlement around 1073 K. Addition of aluminium and iron was found to produce a significant improvement in hydrogen-related embrittlement at room temperature.
Details
- Language :
- English
- ISSN :
- 00222461 and 15734803
- Volume :
- 24
- Issue :
- 12
- Database :
- Supplemental Index
- Journal :
- Journal of Materials Science
- Publication Type :
- Periodical
- Accession number :
- ejs16428040
- Full Text :
- https://doi.org/10.1007/BF00544530