Hot-forged TiAl-based alloy and method for producing the same
AssigneeNational Institute for Materials Science
InventorToshimitsu Tetsui
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Abstract
Provided is a hot-forged TiAl-based alloy of the present invention containing 40 to 45 atom % of Al and additive elements in the following composition ratio (A) or (B), and the balance Ti with inevitable impurities: (A) Nb: 7 to 9 atom %, Cr: 0.4 to 4.0 atom %, Si: 0.3 to 1.0 atom %, and C: 0.3 to 1.0 atom %; and (B) at least one of Cr: 0.1 to 2.0 atom %, Mo: 0.1 to 2.0 atom %, Mn: 0.1 to 4.0 atom %, Nb: 0.1 to 8.0 atom %, and V: 0.1 to 8.0 atom %. The TiAl-based alloy is characterized by having a fine structure of densely arranged lamella grains that are laminated alternately with a Ti3Al phase (α2-phase) and a TiAl phase (γ-phase) and have an average grain size of 1 to 200 μm.
Claims3
A TiAl-based alloy, consisting of:
- Al:
- 41 to 45 atom %,
- Nb:
- 7 to 9 atom %,
- Cr:
- 0.4 to 4.0 atom %,
- Si:
- 0.3 to 1.0 atom %,
- C:
- 0.3 to 1.0 atom %,
- optionally 0.1 to 3 atom % total of at least one element selected from the group consisting of W, Mo, B, Hf, Ta, and Zr, and
- a balance of Ti and inevitable impurities,
- wherein an alloy element parameter P obtained by the following formula is in the composition range of from 1.1 to 2.3;
- P=(41−Al)/3+0.25Nb+0.8Cr−0.8Si−1.7C, and
- the TiAl-based alloy has a fine structure in which lamella grains laminated alternately with a Ti3Al phase (α2-phase) and a TiAl phase (γ-phase) are densely arranged and a β-phase is not included, the lamella grains having an average grain size of 1 to 200 μm.
Dependencies are inferred from the claim text.