Abstract
The self-diffusivities of Ti and Cr were determined in (Ti x W y Cr z )B2 ceramics which are a model system for the development of in-situ reinforced boride ceramics by tailored precipitate formation. Homogeneous solid solutions of composition (Ti0.3W0.5Cr0.2)B2, (Ti0.5W0.3Cr0.2)B2, and (Ti0.4W0.5Cr0.1)B2 were studied in the temperature interval between 1100 and 1500°C, using ion implanted stable 49Ti and 54Cr isotopes and secondary ion mass spectrometry (SIMS). The diffusivities of each element obey an Arrhenius law. The Cr diffusivities of all three compounds can be fitted to a unique Arrhenius line with an activation enthalpy of 3.5 eV and a low pre-exponential factor of 2×10−7 m2/s. The Ti diffusivities are smaller by 1–2 orders of magnitude than the Cr diffusivities, showing, however, higher activation enthalpies of 3.9 eV and approximately the same pre-exponential factors. The consequences of the results for the formation kinetics of precipitates in supersaturated (Ti x W y Cr z )B2 solid solutions are discussed.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
