Creep deformation of a two-phase TiAl/Ti[sub 3]Al lamellar alloy and the individual TiAl and Ti[sub 3]Al constituent phases

Journal Article · Sun Aug 01 00:00:00 EDT 1993 · Scripta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-716X(93)90518-W· OSTI ID:6136555

Bartholomeusz, M F; Wert, J A ^[1]; Yang, Qibin ^[2]

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1. Univ. of Virgina, Charlottesville, VA (United States)
2. Inst. of Metals Research, Shenyang (China)

Two-phase TiAl/Ti[sub 3]Al alloys in which the constituent phases form a lamellar microstructure are reported to possess good combinations of low-temperature fracture toughness, tensile strength and fatigue resistance. However, information about the high-temperature creep properties of the two-phase TiAl/Ti[sub 3]Al alloys with lamellar microstructures (referred to as lamellar alloys in the remainder of the paper) is limited. Based on a simple rule of mixtures model of strength, it would be expected that the creep rates of the lamellar alloy would be between the creep rates of TiAl and Ti[sub 3]Al. In contrast to composite model predictions of strength, Polvani and coworkers found that the minimum creep rates of two duplex alloys, a [gamma]/[gamma][prime] nickel-base superalloy and NiAl/Ni[sub 2]AlTi, were significantly lower than the minimum creep rates of either of the constituent phases. They also reported that most dislocations in the two-phase NiAl/Ni[sub 2]AlTi alloy were contained within the semi-coherent interfacial dislocation networks between the two phases. Based on this observation they proposed that the creep rate is controlled by the rate at which dislocations moving through both phases are emitted and absorbed by the interphase dislocation networks. The greater strain hardening rate of the lamellar TiAl/Ti[sub 3]Al alloy suggests that it may exhibit lower steady-state creep rates that the individual constituent phases. The objective of the present study is to evaluate the creep properties of a TiAl/ Ti[sub 3]Al lamellar alloy and of the individual constituent phases. In this paper, the results of this investigation will be presented and compared with previously published results for this alloy system.

• OSTI ID: 6136555
• Journal Information: Scripta Metallurgica et Materialia; (United States), Vol. 29:3; ISSN 0956-716X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
CREEP
MICROSTRUCTURE
TITANIUM ALLOYS
COMPARATIVE EVALUATIONS
DEFORMATION
FATIGUE
FRACTURE PROPERTIES
INTERMETALLIC COMPOUNDS
MECHANICAL PROPERTIES
STRAIN HARDENING
TENSILE PROPERTIES
ALLOYS
EVALUATION
HARDENING
360103* - Metals & Alloys- Mechanical Properties
360102 - Metals & Alloys- Structure & Phase Studies