The compression behavior of niobium alloyed {gamma}-titanium aluminides
- GKSS Research Centre, Geesthacht (Germany). Inst. for Materials Research
The underlying mechanisms behind the reported high strength of titanium aluminide alloys containing a large addition of niobium has been investigated by determining the flow stresses and activation parameters of plastic deformation. It has been found that alloys such as Ti-45Al-10Nb (at.%) and Ti-45Al-5Nb have 1.25% flow stress values in compression of > 800 MPa at room temperature and > 500 MPa at 1,173 K. When compared with values from a more conventional alloy, Ti-47Al-2Cr-0.2Si, they represent a considerable increase in strength. However, the activation volumes after 1.25% deformation are very similar to those of conventional alloys, particularly up to 973 K. This suggests that athermal dislocation mechanisms are responsible for the increased flow stress of the niobium containing alloys. By comparing the properties of the niobium containing alloys with different binary alloys it has been shown that the high strength is solely a result of the reduced aluminum content and that niobium plays no role in strengthening or work hardening.
- OSTI ID:
- 605838
- Journal Information:
- Acta Materialia, Journal Name: Acta Materialia Journal Issue: 4 Vol. 46; ISSN 1359-6454; ISSN ACMAFD
- Country of Publication:
- United States
- Language:
- English
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