A COMBINED EXPERIMENTAL–NUMERICAL APPROACH TO ASSESS THE EFFECTS OF QUENCHING TRANSFER TIME ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF A TI-6AL-4V ALLOY

This work aimed to develop a combined experimental-numerical approach for the study and prediction of the effects of transfer time to the quenching bath on the microstructure and mechanical properties of the α+β Ti-6Al-4V alloy. The thermal properties of the alloy were validated by comparing numerical and experimental results, the latter obtained at both laboratory and industrial scales, and by adjusting the input simulation data to fit the experimental measurements. To obtain a reliable and validated numerical model, the heat transfer coefficients of air were calculated for the heating and air-cooling processes during the heat treatment steps. Several Ti-6Al-4V samples were subjected to common solutioning, quenching and subsequent aging, considering different quenching delays. The same heat treatment routes were simulated by using the developed model, and the time-temperature curves were calculated for points located at different depths inside the samples. The calculated data were then discussed and compared with the experimental results, showing the model's reliability. The subsequent investigations enabled the establishment of quantitative relationships among the transfer times, the core quenching entry temperatures and the microstructural and mechanical properties of the material. The results showed that for the tested quenching delays, the mechanical and microstructural features of the analysed samples remain unaltered.