Microstructural modelling of the α+β phase in Ti-6Al-4V: a diffusion-based approach

Research output: Contribution to journalArticlepeer-review

Authors

Colleges, School and Institutes

External organisations

  • ESI Group
  • Jiangxi University of Science and Technology

Abstract

Complex heat treatment operations and advanced manufacturing processes such as laser or electron-beam welding will see the metallic workpiece experience a considerable range of temperatures and heating/cooling rates. These intrinsic conditions will have a significant bearing upon the microstructure of the material, and in turn upon the thermo-mechanical properties. In this work, a diffusion-based approach to model the growth and shrinkage of precipitates in the alpha + beta field of the common titanium alloy Ti-6Al-4V is established. Further, the numerical model is extended using a JMA-type approach to explore the dependency of the beta-transus temperature on extremely high heating rates, whereby dissolution alone is too slow to accurately describe the alpha to beta-phase transformation. Experimental heat treatments at rates of 5, 50, and 500 °C/s were performed, and metallographic analysis of the samples was used to validate the numerical modeling framework predictions for lamellar shrinkage, while data from the literature has been used to evaluate the numerical modeling framework for the growth of equiaxed microstructures. The agreement between measurements and numerical predictions was found to be good.

Details

Original languageEnglish
Pages (from-to)2898-2911
Number of pages14
JournalMetallurgical and Materials Transactions B
Volume50
Issue number6
Early online date4 Sep 2019
Publication statusPublished - Dec 2019

Keywords

  • Equiaxed, Lamellar, Alpha, Beta, Titanium