Deformation twinning systems of D0{sub 19} structured Ti-34mol% Al

Journal Article · Tue Aug 01 04:00:00 EDT 1995 · Scripta Metallurgica et Materialia

DOI:https://doi.org/10.1016/0956-716X(95)00260-3· OSTI ID:103605

Lee, J W; Hanada, S ^[1]; Yoo, M H ^[2]

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1. Tohoku Univ., Sendai (Japan). Institute for Materials Research
2. Oak Ridge National Lab., TN (United States). Metal and Ceramics Division

In the present study, deformation modes in Ti{sub 3}Al of the D0{sub 19} structure are examined focusing on twinning. Non-stoichiometric Ti{sub 3}Al was used, since Ohtsuka observed that the formation of deformation twin-like bands become pronounced with a deviation from stoichiometry to an Al-rich composition. The temperature range in which deformation twinning occurs and the crystallographic characteristics of twinning systems in non-stoichiometric Ti{sub 3}Al polycrystals are mentioned. The selected area diffraction pattern evidence of the features identified as deformation twins are presented. Throughout this paper the Miller Bravais indices for the crystallographic elements in the ordered structure are referred to the fundamental hcp crystal structure with the c/a ratio of 1.61. From TEM analysis and two surface trace analysis of deformation twins in non-stoichiometric Ti{sub 3}Al alloy of the D0{sub 19} structure, the following conclusions may be drawn: deformation twinning of Ti-34mol%Al occurs in the temperature range of 1,073K to 1,373K; dominant deformation twinning system is identified as (10{bar 1}1)[10{bar 1}2]. {l_brace}11{bar 2}2{r_brace} and {l_brace}10{bar 1}2{r_brace} twins are also operative with a relatively low density.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 103605
• Journal Information: Scripta Metallurgica et Materialia, Journal Name: Scripta Metallurgica et Materialia Journal Issue: 3 Vol. 33; ISSN SCRMEX; ISSN 0956-716X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
CRYSTAL FACES
GRAIN BOUNDARIES
GRAIN SIZE
HCP LATTICES
INTERMETALLIC COMPOUNDS
OPTICAL MICROSCOPY
ORIENTATION
SAMPLE PREPARATION
TEMPERATURE DEPENDENCE
TITANIUM BASE ALLOYS
TRANSMISSION ELECTRON MICROSCOPY
TWINNING