Abstract
The densification kinetics of Ti-6Al-4V powders with spherical or angular shapes are compared in uniaxial die pressing experiments between isothermal conditions (at 1020 °C, in the β-field, where deformation occurs by creep) and thermal cycling (between 860 and 1020 °C, within the range of the α-β phase transformation of the alloy, where transformation-mismatch plasticity is activated). Densification kinetics are only moderately affected by powder shape, but are markedly faster under thermal cycling than under isothermal conditions, as expected from the higher deformation rate achieved under transformation-mismatch plasticity conditions as compared to creep conditions. The densification curves for both creep and mismatch plasticity deformation mechanisms are successfully modeled for various applied stresses and for partial cycling, when transformation is incomplete. Tensile properties of specimens fully densified under thermal cycling conditions are similar to literature values from Ti-6Al-4V densified by isothermal hot isostatic pressing.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 3851-3859 |
| Number of pages | 9 |
| Journal | Acta Materialia |
| Volume | 58 |
| Issue number | 11 |
| DOIs | |
| State | Published - Jun 2010 |
Funding
This research was supported by a grant from the Boeing Company . The authors thank Mr. L.C. Firth (The Boeing Company) for useful discussions. This paper is dedicated to the memory of Dr. W.B. Crow (The Boeing Company) who made numerous important contributions to the present research.
Keywords
- Hot pressing
- Phase transformations
- Powder consolidation
- Superplasticity
- Titanium
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Polymers and Plastics
- Metals and Alloys