Effects of Cooling Rate on the Microstructure and Mechanical Properties of Ti-6Al-4V Alloy
The Ti-6Al-4V alloy were solution heat-treated at 960°C for 1 hour and then cooling by water-quenching immediately and 2 bar argon atmosphere, respectively. After being aged at 550°C for 5 hours, the tensile and Charpy impact test were performed. Based on the results, it is found that the quantity of primary α grains will increasing with decreasing the cooling rate following the solution heat treatment, and which will result in the tensile strength and toughness decreasing. Moreover, the optical and SEM micrographs indicated that the cracks propagated with traversing the prior β grains and propagating along the primary α grain boundaries in both of the tensile and impact fractured specimens. This implies that the strength of α grain boundary is less than that of α grain, which will play an important role on the mechanical properties of tensile strength and toughness.
S. C. Jeng and H. S. Chiou, "Effects of Cooling Rate on the Microstructure and Mechanical Properties of Ti-6Al-4V Alloy", Applied Mechanics and Materials, Vols. 284-287, pp. 103-107, 2013