Symposium: Deformation and Transitions at Grain Boundaries

Metallurgical and Materials Transactions A

, Volume 43, Issue 10, pp 3570-3585

Variant Selection During Cooling after Beta Annealing of Ti-6Al-4V Ingot Material

  • G. A. SargentAffiliated withUES, Inc. Email author 
  • , K. T. KinselAffiliated withMechanical Engineering Department, Wright-State University
  • , A. L. PilchakAffiliated withAir Force Research Laboratory, Materials and Manufacturing Directorate, AFRL/RXLM
  • , A. A. SalemAffiliated withMaterials Resources LLC
  • , S. L. SemiatinAffiliated withAir Force Research Laboratory, Materials and Manufacturing Directorate, AFRL/RXLM


The selection of alpha variants during the cooling of Ti-6Al-4V from the beta-phase field was investigated. For this purpose, samples with a coarse, columnar beta-grain structure with a 〈100〉 fiber texture were extracted from an as-cast production-scale ingot. The alpha variants in the as-cast samples as well as those produced during several successive beta-annealing treatments were determined using electron backscatter diffraction (EBSD). The EBSD results indicated that a subset of the 12 possible variants was developed within each grain; the specific variants were a function of the cooling rate after beta heat treatment. Moreover, the generation of similar variants during successive heat treatments involving an identical cooling rate suggested a noticeable memory effect. The variant selection process was rationalized based on calculations of the strain associated with the beta-to-alpha transformation. These calculations revealed that the overall aggregate strain approached zero in both the as-cast condition as well as after beta heat treatment, suggesting the occurrence of a long-range self-accommodation mechanism.