Ultrasonic velocity variation of Ti6Al4V Ti-alloy bars under conventional forging combined with triple heat treatmentFeixiao Han, Fengqi Hou, Xiaoping Sun, Zhixia Liu, Yonggang He and Kaixuan WangMATEC Web Conf., 321 (2020) 12035DOI: https://doi.org/10.1051/matecconf/202032112035