Abstract
Two Ti–6Al–6V–2Sn alloys, with globular and lamellar microstructures, are deformed at 750°C during tensile and compression tests. The lamellar microstructure shows softening and higher peak stress values than the globular microstructure as a consequence of the Hall–Petch effect. In-situ high energy synchrotron diffraction experiments allow characterization of the load partition between α- and β-phases, plastic deformation mechanisms and texture evolution. The α-phase deforms mainly by rotation while the β-phase deforms by misorientation formation, acting merely as load transfer agent. The Taylor factor evolution of the α-phase and the annihilation of dislocations are analyzed qualitatively and quantitatively. The Taylor factor is connected to both the softening observed in the alloy with the lamellar microstructure and the texture development.
Highlights
The microstructure of titanium alloys can be tailored applying thermo-mechanical treatments without modification of their chemical composition
Ti662 alloys produced by two different processing routes were investigated: ingot metallurgy (IM) and powder metallurgy (PM)
The maximum strength for the IM alloy during tensile loading is about 120 MPa, while this stress is reached at the end of the compression test
Summary
The microstructure of titanium alloys can be tailored applying thermo-mechanical treatments without modification of their chemical composition. The morphology, distribution and amount of allotropic phases play an important role for the elastic properties as well as for the plastic behaviour. They do not provide information about load partition in multiphase materials, elastic anisotropies of crystallographic planes, etc., and cannot be used to study the deformation mechanisms taking place in the different allotropic phases. These tests are usually combined with n Corresponding author at: Institute of Materials Science and Welding, Graz University of Technology, Kopernikusgasse 24/I, A-8010 Graz, Austria
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