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Influence of Controlled Cooling Rates During Thermal Processing of Ti 6% Al 4% V Alloys Using In-Situ Scanning Electron Microscopy

Published online by Cambridge University Press:  13 April 2020

Genevieve A Kane ,
M. David Frey  and
Robert Hull
Genevieve A Kane*
Affiliation:
Department of Materials Science and Engineering Center for Materials, Devices and Integrated Systems, Rensselaer Polytechnic Institute, 110 8th Street Troy, NY, 12180
M. David Frey
Affiliation:
Center for Materials, Devices and Integrated Systems, Rensselaer Polytechnic Institute, 110 8th Street Troy, NY, 12180
Robert Hull
Affiliation:
Department of Materials Science and Engineering Center for Materials, Devices and Integrated Systems, Rensselaer Polytechnic Institute, 110 8th Street Troy, NY, 12180
*
*(Email: [email protected])
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Abstract

We describe experimental approaches to real time examination of the microstructural evolution of Ti 6%Al 4%V upon cooling from above the beta transus (~995 °C) while imaging in the scanning electron microscope. Ti 6%Al 4%V is a two phase, α+β titanium alloy with high strength and corrosion resistance. The β →α transformation on cooling can give rise to different microstructures and properties through various thermal treatments. Fully lamellar microstructures, bi-modal microstructures, and equiaxed microstructures can each be obtained by accessing different cooling rates upon the final treatment above the beta temperature, each resulting in uniquely enhanced material properties.

Utilizing the capabilities of a heating/ tensile stage developed by Kammrath & Weiss Inc., are able to apply real-time imaging techniques in the scanning electron microscope to monitor the development of the microstructure. Annealing temperatures up to 1100 °C are attainable, with cooling rates ranging from 0.1 ° C per second to 3.3 °C per second. This has allowed us to directly observe the formation of lamellae at different annealing temperature/ cooling rate combinations to determine the lamellar microstructure width, separation, and colony size.

Keywords

scanning electron microscopy (SEM)microstructurealloyTi
Type
Articles
Information
MRS Advances , Volume 5 , Issue 29-30: Materials Theory, Computation and Characterization , 2020 , pp. 1603 - 1611
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Copyright
Copyright © Materials Research Society 2020

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