Portevin-Le Chatelier instabilities and stoichiometric effects in B2 titanium aluminides

Journal Article · Fri Mar 15 00:00:00 EST 1996 · Scripta Materialia

DOI:https://doi.org/10.1016/1359-6462(95)00609-5· OSTI ID:215376

Popille, F; Kubin, L P; Douin, J; Naka, S ^[1]

---

1. CNRS-ONERA, Chatillon (France)

The mechanical properties of a Ti{sub 53}Al{sub 25}Nb{sub 22} (at.%) alloy has been investigated over a large temperature range. The as-cast alloy is two-phased and contains an ordered b.c.c. (B2) phase and an ordered orthorhombic (O) phase. With appropriate heat treatments, a single phased alloy with either the B2 structure or the O structure can be obtained. The present paper reports on the observation of plastic instabilities in the B2 phase in the temperature range from 200 C to 450 C. It is shown that jerky flow in these compounds can be identified with Portevin-Le Chatelier (PLC) instabilities. The nature of the solute atom responsible for these dynamic strain aging effects is examined through the influence of alloy composition on the occurrence of unstable plastic flow. For this purpose, investigations on several TiAlMo and TiAlMoNb single phase B2 alloys, which also exhibit the PLC effect, have been performed. As a result, a new explanation is proposed for the occurrence of jerky flow in this class of intermetallic alloys.

• OSTI ID: 215376
• Journal Information: Scripta Materialia, Vol. 34, Issue 6; Other Information: PBD: 15 Mar 1996
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
33 ADVANCED PROPULSION SYSTEMS
TITANIUM ALLOYS
PORTEVIN-LE CHATELIER EFFECT
STOICHIOMETRY
MECHANICAL PROPERTIES
ALUMINIUM ALLOYS
MOLYBDENUM ALLOYS
NIOBIUM ALLOYS
AEROSPACE INDUSTRY
MATERIALS
INTERMETALLIC COMPOUNDS
BRITTLENESS
SLIP
FRACTURE PROPERTIES
DEFORMATION
PLASTICITY
STRAIN AGING
CHEMICAL COMPOSITION