Flow softening during hot working of Ti-6Al-4V with a lamellar colony microstructure
The production of conventional alpha/beta titanium alloys for aerospace applications is often based on an ingot metallurgy approach comprising melting and a series of hot working and heat treatment steps. Recent research has probed the effect of factors such as prior-beta grain size, strain rate, and temperature on plastic flow and microstructure evolution during hot forging of Ti-6Al-4V with a lamellar colony microstructure. In particular, the flow softening response evident in true stress-strain curves determined from isothermal hot compression tests has been studied in an attempt to ascertain the important deformation mechanism. The objective of the present work was to determine if crystallographic texture changes, as characterized by nominally uniform rotation of the alpha phase, or platelet kinking within the lamellar colonies are major considerations that can explain the flow softening observations. This understanding is very important with regard to the eventual development of models for the prediction and control o texture and hence properties such as stiffness and fatigue resistance. To this end, the flow response during both isothermal, hot compression and hot tension testing was measured and interpreted with the aid of finite element and polycrystalline plasticity modeling.
- Research Organization:
- Materials and Manufacturing Directorate, Air Force Research Lab., Wright-Patterson Air Force Base, OH (US)
- OSTI ID:
- 20023100
- Journal Information:
- Scripta Materialia, Vol. 40, Issue 12; Other Information: PBD: 21 May 1999; ISSN 1359-6462
- Country of Publication:
- United States
- Language:
- English
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