The microstructure development of lamellar structure of an orthorhombic Ti2AlNb-based Ti？22Al？26Nb？1Zr alloy, includingB2 decomposition and spheroidization ofO phase, was investigated. The results show that the lam...The microstructure development of lamellar structure of an orthorhombic Ti2AlNb-based Ti？22Al？26Nb？1Zr alloy, includingB2 decomposition and spheroidization ofO phase, was investigated. The results show that the lamellar structure is fabricated by heating the samples in the singleB2 phase field and cooling slowly in the furnace. Aging treatments are conducted in the （O＋B2） phases field by air cooling. After aging at 700 °C for a short time within 100 h, there is no significant change of microstructures, whereas the coarsening of lamellae is observed in the long-term aged microstructure. Ti？22Al？26Nb？1Zr alloy exhibits microstructural instability including the severe dissolution ofB2 lamella, discontinuous precipitation and spheroidization of O phase during the long term aging process at 700 °C up to 800 h. In addition, a pronounced formation of branch-shapedO phase lamella is observed for the alloy aged over 100 h.展开更多
基金Project(2011CB605503)supported by the National Basic Research Program of ChinaProject(51371144)supported by the National Natural Science Foundation of China
文摘The microstructure development of lamellar structure of an orthorhombic Ti2AlNb-based Ti？22Al？26Nb？1Zr alloy, includingB2 decomposition and spheroidization ofO phase, was investigated. The results show that the lamellar structure is fabricated by heating the samples in the singleB2 phase field and cooling slowly in the furnace. Aging treatments are conducted in the （O＋B2） phases field by air cooling. After aging at 700 °C for a short time within 100 h, there is no significant change of microstructures, whereas the coarsening of lamellae is observed in the long-term aged microstructure. Ti？22Al？26Nb？1Zr alloy exhibits microstructural instability including the severe dissolution ofB2 lamella, discontinuous precipitation and spheroidization of O phase during the long term aging process at 700 °C up to 800 h. In addition, a pronounced formation of branch-shapedO phase lamella is observed for the alloy aged over 100 h.
