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

Journal Article · Thu Mar 14 23:00:00 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]

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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, Journal Name: Scripta Materialia Journal Issue: 6 Vol. 34; ISSN 1359-6462; ISSN XZ503X
• Country of Publication: United States
• Language: English

Related Subjects

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