Benoît Denand

β → β + α Isothermal Phase Transformation in Ti17 Titanium Alloy: Chemical Composition and Crystallographic Aspect

The partitioning of alloying elements between a and b phases was measured at different steps of the isothermal transformation at 710 and 610°C in Ti 17 alloy using EDX analyzer in the TEM. In addition, the transformation crystallography was determined. No differences in substitution elements were observed for a same transformation temperature in the a phase, however the composition varied with the transformation temperature. For the partial transformed specimens, gradient in composition were obtained. Results are compared to calculated compositions using ThermoCalc software and Saunders database.

In Situ Stress Tensor Determination during Phase Transformation of a Metal Matrix Composite by High-Energy X-ray Diffraction

In situ high-energy X-ray diffraction using a synchrotron source performed on a steel metal matrix composite reinforced by TiC allows the evolutions of internal stresses during cooling to be followed thanks to the development of a new original experimental device (a transportable radiation furnace with controlled rotation of the specimen). Using the device on a high-energy beamline during in situ thermal treatment, we were able to extract the evolution of the stress tensor components in all phases: austenite, TiC, and even during the martensitic phase transformation of the matrix.