Microstructure-property relationships of two Ti2AlNb-based intermetallic alloys: Ti-15Al-33Nb(at.%) and Ti-21Al-29Nb(at.%)

Christopher J. Cowen, Dingqiang Li, Carl J. Boehlert

Research output: ResearchConference contribution

Abstract

Two Ti2AlNb intermetallic orthorhombic (O) alloys, Ti-15Al-33Nb and Ti-21Al-29Nb(at.%), were subtransus processed into sheets, using pancake forging and hot-pack rolling, and evaluated in tension (25 and 650°C) and creep (650-710°C) and the properties and deformation behavior were related to microstructure. Some of the microstructural features evaluated were grain boundary character, grain size, phase volume fraction, and morphology. The alloy Al content was important to strength and elongation-to-failure (εf), where higher Al contents lead to greater tensile strengths and lower εf values and a corresponding brittle fracture response. However, the room temperature (RT) strengths of Ti-15Al-33Nb, which exhibited greater BCC phase volume fractions than Ti-21 Al-29Nb and ductile failure (εf > 2%), were always greater than 775 MPa. The creep stress exponents (n) and activation energies (Qapp) suggested that a transition in the dominant creep deformation mechanism exists and is dependent on stress and microstructure. Supertransus heat treatment, which increased the prior-BCC grain size and resulted in a lath-type O+BCC microstructure, resulted in reduced creep strains and strain rates. In fact, the supertransus heat-treated Ti-15Al-33Nb microstructures exhibited greater creep resistance than subtransus heat-treated Ti-21Al-29Nb microstructures. Combining the creep observations with the tensile response, the supertransus heat treated Ti-15Al-33Nb lath O+BCC microstructures exhibited the most attractive combination of tensile strength, εf values, and creep resistance.

LanguageEnglish (US)
Title of host publicationMaterials Research Society Symposium Proceedings
EditorsM.J. Mills, H. Inui, H. Clemens, C.-L. Fu
Pages235-240
Number of pages6
Volume842
StatePublished - 2005
Externally publishedYes
Event2004 MRS Fall Meeting - Boston, MA, United States
Duration: Nov 29 2004Dec 1 2004

Other

Other2004 MRS Fall Meeting
CountryUnited States
CityBoston, MA
Period11/29/0412/1/04

Profile

Intermetallics
Microstructure
Creep
Hot Temperature
Creep resistance
Volume fraction
Tensile strength
Hot rolling
Brittle fracture
Forging
Application programs
Strain rate
Elongation
Grain boundaries
Activation energy
Heat treatment
Temperature

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials

Cite this

Cowen, C. J., Li, D., & Boehlert, C. J. (2005). Microstructure-property relationships of two Ti2AlNb-based intermetallic alloys: Ti-15Al-33Nb(at.%) and Ti-21Al-29Nb(at.%). In M. J. Mills, H. Inui, H. Clemens, & C-L. Fu (Eds.), Materials Research Society Symposium Proceedings (Vol. 842, pp. 235-240). [S7.9]

Microstructure-property relationships of two Ti2AlNb-based intermetallic alloys : Ti-15Al-33Nb(at.%) and Ti-21Al-29Nb(at.%). / Cowen, Christopher J.; Li, Dingqiang; Boehlert, Carl J.

Materials Research Society Symposium Proceedings. ed. / M.J. Mills; H. Inui; H. Clemens; C.-L. Fu. Vol. 842 2005. p. 235-240 S7.9.

Research output: ResearchConference contribution

Cowen, CJ, Li, D & Boehlert, CJ 2005, Microstructure-property relationships of two Ti2AlNb-based intermetallic alloys: Ti-15Al-33Nb(at.%) and Ti-21Al-29Nb(at.%). in MJ Mills, H Inui, H Clemens & C-L Fu (eds), Materials Research Society Symposium Proceedings. vol. 842, S7.9, pp. 235-240, 2004 MRS Fall Meeting, Boston, MA, United States, 11/29/04.
Cowen CJ, Li D, Boehlert CJ. Microstructure-property relationships of two Ti2AlNb-based intermetallic alloys: Ti-15Al-33Nb(at.%) and Ti-21Al-29Nb(at.%). In Mills MJ, Inui H, Clemens H, Fu C-L, editors, Materials Research Society Symposium Proceedings. Vol. 842. 2005. p. 235-240. S7.9.
Cowen, Christopher J. ; Li, Dingqiang ; Boehlert, Carl J./ Microstructure-property relationships of two Ti2AlNb-based intermetallic alloys : Ti-15Al-33Nb(at.%) and Ti-21Al-29Nb(at.%). Materials Research Society Symposium Proceedings. editor / M.J. Mills ; H. Inui ; H. Clemens ; C.-L. Fu. Vol. 842 2005. pp. 235-240
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