Effect of Prior b Processing on Superplasticity of (a þ b) Thermomechanically Treated Ti–6Al–4V Alloy Indranil Lahiri, * Debrupa Lahiri (Mondal), # and S. Bhargava Department of Materials and Metallurgical Engineering, Indian Institute of Technology, Kanpur, India ABSTRACT A new thermomechanical schedule involving processing in b and (a þ b) phase fields for obtaining good superplastic properties in Ti–6Al–4V alloy has been proposed and tested for optimum superplasticity. Superplastic behavior of the as-rolled and annealed sheets has been studied systematically. It has been inferred that in addition to grain size, prior b processing and annealing in the (a þ b) phase field also have a marked effect on superplasticity of the alloy sheets. As-rolled sheets in (a þ b) phase field having undergone annealing in (a þ b) phase field with prior b rolling exhibit maximum superplastic elongation. Key Words: Ti–6Al–4V alloy; b processing; (a þ b) processing; Grain size; Aspect ratio; m value. *Correspondence: Indranil Lahiri, Non-Ferrous Materials Technology Development Centre, Hyderabad-500 058, India; Fax: 91-40-24340592; E-mail: indranil78@yahoo.com. # Current Address: Nuclear Fuel Complex, Hyderabad-500 062, India. MATERIALS AND MANUFACTURING PROCESSES Vol. 18, No. 4, pp. 621–635, 2003 621 DOI: 10.1081/AMP-120022501 1042-6914 (Print); 1532-2475 (Online) Copyright # 2003 by Marcel Dekker, Inc. www.dekker.com