Prediction of Mechanical Properties of Ti-6Al-4V Forgings Based on Simulation of Microstructure Evolution

Abstract

Titanium alloys are widely used in the aerospace industry as a structural material. Since this application is critical, the titanium alloys must have high mechanical properties both at room and at elevated temperatures. The thermomechanical processing of titanium alloys during forging determines the microstructure of the manufactured parts to a large extend. The final mechanical properties are attained by the subsequent heat treatment. Hardening heat treatment, such as solid solution treatment and aging, improves both the strength and ductility of the material. Simulation of metal forming processes with the evolution of the microstructure and prediction of the final mechanical properties are extremely important and allow to effectively develop a technological process for the production of high-quality parts. The most widely used titanium alloy is Ti-6Al-4V, which combines high mechanical properties and satisfactory processability and can be used at temperatures up to 350 °C. In this work samples of Ti-6Al-4V alloy having a lamellar structure with different morphology and a duplex structure with different globular alpha-phase fractions and average grain sizes have been studied. The mechanical properties at the room temperature were determined using compression tests. These experimental data were used to develop a model that allows for predicting the mechanical properties of Ti-6Al-4V alloy forgings after the final heat treatment. The model has been tested by forging a turbine blade using the QForm software.