Quantitative microstructural analysis of Ti-6Al-4V alloy after hot forging process by means of stereological morphometry

Research on feasible and rigorous models capable of quantifying various microstructures have been received great attention due to their importance to the properties of titanium alloys. The complexity and diversity of microstructural information makes it rather difficult to quantify. In the present work, we present an automatic method to investigate the microstructural features of Ti-6Al-4V titanium alloy after hot forging. Standardized stereology protocol and quantitative metallography rules were used to characterize and quantify microstructure features quickly. The forging experiment are performed on a 3-ton hammer in the temperature range from 930°C to 1030°C with 20°C interval, and at different deformation of 20 %, 50 % and 80 %, respectively. The characterization of microstructure for specimens deformed to different temperatures and deformation degrees were examined. These microstructural features mainly include phase volume fraction, β grain size, thickness of α phase, and the morphology of α-phase, etc. Six steps on image processing were presented. The results indicated the tremendous potential of these models and methods to characterize microstructures using advanced techniques, which are feasible, and explained with some examples.