Microstructure development during conventional and isothermal hot forging of a near-gamma titanium aluminide

Journal Article · Thu Dec 01 04:00:00 EST 1994 · Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)

DOI:https://doi.org/10.1007/BF02649227· OSTI ID:6874812

Semiatin, S L ^[1]; Seetharaman, V ^[2]; Jain, V K ^[3]

---

1. Wright Lab. Materials Directorate, Wright-Patterson Air Force Base, OH (United States)
2. UES, Inc., Dayton, OH (United States)
3. Univ. of Dayton, OH (United States). Mechanical and Aerospace Engineering Dept.

The breakdown of the lamellar preform microstructure in the ingot metallurgy near-gamma titanium aluminide, Ti-45.5Al-2Cr-2Nb (atomic percent), was investigated. Microstructures developed during canned, conventional hot forging were compared to those from isothermal hot forging. The higher rate of deformation in conventional forging led to considerably finer and almost completely broken-down structures in the as-forged condition. Several nontraditional approaches, including the isothermal forming of a metastable microstructure (so-called alpha forging'') and the inclusion of a short static recrystallization anneal during forging, were found to produce a more fully broken-down structure in as-isothermally forged conditions. Despite the noticeable microstructure differences after forging, a conventionally and isothermally forged material responded similarly during heat treatment. In both cases, almost totally recrystallized structures of either equiaxed gamma or transformed alpha grains surrounded by fine gamma grains were produced depending on the heat-treatment temperature. Metallography on forged and heat-treated pancake macroslices was useful in delineating small differences in composition not easily detected by analytical methods.

• OSTI ID: 6874812
• 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. 25:12; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101 -- Metals & Alloys-- Preparation & Fabrication
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
ALUMINIUM ALLOYS
CHEMICAL COMPOSITION
CHROMIUM ALLOYS
FABRICATION
FORGING
HOT WORKING
MATERIALS WORKING
MICROSTRUCTURE
TITANIUM ALLOYS
VANADIUM ALLOYS