Effect of Oxygen Content of Powders on Previous Particle Boundaries in Hot Isostatic Pressed TiAl Alloy
Argon gas atomized Ti–43Al–9V–0.3Y alloy powders with oxygen contents of 1150 and 550 ppm respectively were hot isostatic pressed (HIPed) at 1200 °C and 150 MPa for 3 h to obtain full density compacts. The effect of powders oxygen content on previous particle boundaries (PPBs) was investigated. Results show that PPBs only were observed in the HIPed compact produced from the powders with 1150 ppm oxygen content, and higher oxygen content promoted the formation of PPBs in TiAl alloy. SEM and TEM analysis proved that the microstructure at PPBs was α2/γ lamellar. Oxygen was the α2 phase stabilizer, and it restricted the α → γ transformation but drived the α → α2 + γ eutectoid process in which the lamellar formed.
KeywordsOxygen content Previous particle boundaries TiAl alloy Hot isostatic pressing
This research was funded by the National Natural Science Foundation of China under Contract No. 51434007, No. U1435203 and No. 51301157.
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