An Electron Microscope study of structure of high damping capacity Ti - 644 casting titanium alloy during the quenching and aging

Ti-6A1-4V-4Mo casting titanium alloy is a new high damping capacity α + β martensitic titanium alloy, which suits for the manufacture of rotating blades particularly of large sizes or for highspeed operations. It was found that a remarkable improvement in damping capacity is made possible by rapidly cooling the alloy from a proper temperature in the α + β phase temperature range after heating a predetermined time. Especially the alloy will have the highest damping capacity when heating in the 850-900°C temperature range.Fig. 1 Shows the relation between the damping capacity of the alloy and solution treatment temperatures. It also was found that damping capacity of the alloy decreases when the specimens were reheated at, 150-300 ° C temperature range for a certain time after solution treatment, the results show in Fig. 2.