Microstructural evolution of a Ti-6Al-4V alloy during thermomechanical processing

Abstract

Variation of microstructure of a Ti-6A1-4V alloy during thermomechanical processing at a range of hot working conditions (temperature: 850-1050 °C, strain rate: 0-1.0 s-1has been investigated for further understanding and control of the processing-structure-property relationships. The influences of hot working parameters on deformation localization, width of α platelets, (α → β) phase transformation, and (meta)dynamic recrystallization were systematically examined by optical microscopy and scanning electron microscopy. The experimental results showed that the lamellar morphology of the α phase can be sub-divided into five different categories for samples processed in the (α + β) phase field, and these represent three stages of the (α → β) phase transformation. It was also noted that a certain degree of the (α → β) phase transformation occurred concurrently with the mechanical deformation in the (α + β) phase field. The experimental evidence suggests that dynamic and/or metadynamic recrystallization has occured in the β phase field, but was not involved in the (α + β) phase field under the experimental conditions. © 2002 Elsevier Science B.V. All rights reserved.