Submicron Grain Size Formation in Thermohydrogenated and Deformed Ti-6Al-4V: The Effect of Processing Route on the Degree of Grain Refinement

Abstract:

The aim of this work was to refine the as-cast Ti-6Al-4V grain size and its Widmanstätten morphology to optimise the mechanical performance of Ti-6Al-4V castings. Hydrogenation and deformation were used as variables in processing routes aimed at assessing the degree of refinement in the as-cast Ti-6Al-4V microstructure. Thermohydrogen processing (THP) refined the Widmanstätten morphology and not the prior beta grain boundary network. Therefore, the degree of refinement in THP processing is limited to morphology refinement within pre-existing prior beta grains. Deformation processing and recrystallisation is necessary to eliminate the indelible influence of the prior beta grain boundary network on the extent of THP refinement. In this context, a substantial degree of refinement is achieved from thermohydrogen and deformation processing (THDP). The as-cast Ti-6Al-4V grain boundary network was refined from an average diameter of 2000μm to 20μm. In addition, the Widmanstätten morphology was refined to submicron equiaxed alpha and beta grains.

• Periodical: Advanced Materials Research (Volume 1019)
• Pages: 266-272
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.1019.266
• Online since: October 2014
• Authors: V.N. Vilane*, R.D. Knutsen, J.E. Westraadt
• Keywords: Deformation Processing, Grain Refinement, Hydrogen Alloying, Ti-6Al-4V Alloy

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