Physical constants, deformation twinning, and microcracking of titanium aluminides

Journal Article · Thu Jan 01 04:00:00 EST 1998 · Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science

DOI:https://doi.org/10.1007/s11661-998-0158-2· OSTI ID:605809

Yoo, M H; Fu, C L ^[1]

---

1. Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

Physical properties that are relevant to mechanical behavior of single-phase TiAl and Ti{sub 3}Al and two-phase TiAl/Ti{sub 3}Al alloys are summarized. By using planar-fault energies and temperature-dependent elastic constants, dislocation dissociation reactions applicable to twin formation in TiAl are analyzed, and a pole mechanism based on a jogged [110]/2 ordinary dislocation is proposed to explain the available experimental data on deformation twinning in {gamma}-TiAl single crystals. The strong plastic anisotropy reported in TiAl polysynthetically twinned (PST) crystals is attributed in part to the localized slip along lamellar interfaces, thus lowering the yield stress for soft orientations. The experimental findings reported on cleavage habit planes of PST crystals are discussed in terms of the calculated ideal work of adhesion and possible extrinsic factors.

• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-96OR22464
• OSTI ID: 605809
• Journal Information: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Journal Name: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science Journal Issue: 1 Vol. 29; ISSN 1073-5623; ISSN MMTAEB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
CRACK PROPAGATION
DEFORMATION
DISLOCATIONS
GRAIN ORIENTATION
INTERMETALLIC COMPOUNDS
TITANIUM ALLOYS
TWINNING