摘要
通过等温锻造方法对Ti-47Al-5(C+V+Mo+Nb)(at%)合金进行组织控制。研究发现,由于合金在凝固过程中存在两个包晶反应,导致枝晶间铝含量的分布极不平衡,从而使铸锭组织不均匀,含有大量的γ+α2片层组织。在热加工中,片层组织在大变形量下发生剪切变形或严重弯曲。剪切变形组织沿平行于片层边界作用,使各片层团间产生大量再结晶晶粒并呈无序生长;而由于γ和α2取向关系发生畸变,γ和α2由片层形式趋向于等轴。本研究还对γ-TiAl合金再结晶机理进行了讨论。
Controlling microstructure of Ti-47 Al-5 (C r+V+Mo +Nb ) ally by means of isothermal forging has been studied. Results show that distribution of aluminium atoms in dendritic Structure is inhomgeneous because of the two peritectic reaction during cooling of γ-ToAl ingot, which results in a number of lamellar (γ+α2) structures. Shearing strain and heaVy bending in lamellar structure of γ-TiAl alloy can be caused by heavy deformation during hot working. The shearing strain, which is parallel to the boundaries of lamellar structure, can make lamellar structure produce a lot of dynamic recrystallized structures and the grains grow up irregularly. Because the orientation of γ and α2 grains of lamellar structure with heaVy bending is distorted, the γand α2 grains do not exist as lamellar structure, but as equiaxel one. Mechanism of dynamic recrystallization of γ-TiAl alloy is also studied.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
1996年第3期22-25,共4页
Rare Metal Materials and Engineering
关键词
等温锻造
组织
再结晶
钛铝合金
金属间化合物
iAl alloy, isothermal forging, controlling microstructure, recrystallization