Deformation and microstructure in L1[sub 0] type Ti-Al-V alloys

Journal Article · Sun Jan 01 04:00:00 EST 1995 · Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)

OSTI ID:6874044

Hahn, Y D ^[1]; Whang, S H ^[2]

---

1. Korea Inst. of Machinery and Metals, Chang-Won (Korea, Republic of)
2. Polytechnic Univ, Brooklyn, NY (United States). Dept. of Metallurgy and Materials Science

The addition of vanadium to polycrystalline, single-phase [gamma]-TiAl significantly enhances stiffness from room temperature (RT) to 1,173 K. The maximum yield stress in Ti-55Al-10V alloy is centered near 1,073 K, in contrast with those of single-crystal Ti-54Al at 873 and 1073 K, depending upon deformation orientation. The effect of strain rate on yield stress is present over the entire temperature range, but it is more prominent above 873 K, while the effect becomes significantly small between 673 and 873 K, similar to that observed in L1[sub 2] type Ni[sub 3]Al. The microstructure of deformed Ti-55Al-10V and Ti-49.5Al-10V alloys evolved by slip, twinning, and formation of stacking faults. Twinning is a major deformation mode in Ti-49.5-10V alloy and a minor mode in Ti-55Al-10V. It appears that the amount of twins for a given deformation decreases with increasing Al content. The twin structures in both alloys were found to be true twins of (111) [112]. No pseudotwinning was observed in the alloys deformed in the temperature range of RT to 1,273 K. The stacking faults found in the deformed alloys had an extrinsic character. No intrinsic type of stacking faults were found in these alloys. In addition to the cross slip of superdislocations, the anomalous hardening up to 1,073 K appears attributable to an ordinary superdislocation pinning structure, dislocation loops, and nonglissile square shaped dislocations,'' which are products of super-superdislocation reaction. These nonglissile or pinning structures are unwinded in the deformed Ti-55Al-10V alloy at 1,273 K, consistent with the softening behavior at this temperature.

• OSTI ID: 6874044
• Journal Information: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States), Journal Name: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States) Vol. 26:1; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102 -- Metals & Alloys-- Structure & Phase Studies
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
ALUMINIUM ALLOYS
DEFORMATION
ELEMENTS
MECHANICAL PROPERTIES
METALLURGICAL EFFECTS
METALS
MICROSTRUCTURE
TITANIUM ALLOYS
TRANSITION ELEMENTS
VANADIUM
VANADIUM ALLOYS