Investigations of Formability and Dynamic Recrystallization Development of Titanium Alloys During Dieless Wire Drawing Processes

Abstract

This study investigates the formability and grain size evolution during the dieless wire drawing process of titanium alloy Ti–6Al–4V. First, thermocompression tests of Ti–6Al–4V billets are conducted to obtain their flow stresses at different temperatures and strain rates. Dynamic recrystallization (DRX)‐related constants and grain size prediction models for titanium alloy Ti–6Al–4V are established from the flow stress curves through regression analyses. Then, a finite element software DEFORM 2D coupled with the established DRX models is adopted for DRX volume fraction and grain size evolution simulations of titanium alloy Ti–6Al–4V during dieless wire drawing processes. The effects of various drawing conditions, such as drawing speed, drawing temperature, and area reduction, on the formability of the wire after the dieless drawing process are discussed. Finally, a dieless drawing machine with a high‐frequency induction heating apparatus and a cooling system is developed. A series of experiments of dieless drawing of titanium alloy Ti–6Al–4V wires at different drawing speeds, drawing temperatures, and cooling rates are conducted. The analytical forming limits of area reductions and grain sizes are compared with experimental values to validate the finite element analysis and DRX models.