XU Dongsheng
,
SONG Yan
,
LI Dong
,
HU Zhuangqi(Institute of Metal Research
,
Chinese Academy of Sciences
,
Shenyang
,
China)(Northeastern University
,
Shenyang
,
China)
金属学报(英文版)
A method based on electronic structure calculation is proposed to predict the substitution behavior of elements in ordered intermetallics. The electronic structure of 20 alloying elements in TiAl is calculated using the DV-Xα cluster method The bond orders between alloying elements and surrounding atoms, Bo_Ti,Bo_Al, are used as parameters. Two lines on the Bo_Ti-Bo_Al diagram separate the elements into three groups. The elements located outside of the two lines substitute either Ti or Al atom regardless of the composition of TiAl. The substitution behavior of elements between the two lines will be affected by the Ti/Al ratio and the amount of alloying elements added Substituting sequence in multi-element alloy is discussed The prediction based on this method agrees well with the experimental results.
关键词:
: substitution behavior; site occupancy; intermetallic compound
,
null
LI Geping
,
GUAN Shaoxuan
,
WANG Qingjiang
,
LIU Yuyin
,
LI Dong
,
HU Zhuangqi (Institute of Metal Researeh
,
Chinese Academy of Sciences
,
Shenyang
,
China Manuscript received 23 January. 1995)
金属学报(英文版)
The morphologies of the Nd-rich phase particles in the Ti-5Al-4Sn-2Zn -1Mo-0.25Si-1Nd alloy after high temperature deformation are investigaied by optical microscope and transmission electron microscope. It is found that the Nd-rich phase particles are 1.0～14 μm in diameter and uniformly distributed in ihe matrix, and the majority of the particles are elliptical. Under high temperature deformaiton, high stress concentration occurs on the particles, the particles near to sphericity are obtained.
关键词:
: Ti alloy
,
null
,
null
LI Geping
,
LI Dong
,
LIU Yuyin
,
HU ZhuangqiInstitute of Metal Research
,
Chinese Academy of Sciences
,
Shenyang
,
China
金属学报(英文版)
For the as-cast Ti-55 alloy, the morphology of the alloy riser consists of coarse dendrite zone and equiaxial grain zone. The second phase particles are 2.0-25 um in diameter. Some particles appear at grain boundaries, the others precipitate within grains. The shapes of the particles are mainly ellipsoids, and a few kinds of short needle-like and block v morphologies. The Nd-rich phase particles are enriched in the liquid before the inter face and are engulfed along the solidification plane-front. Finally, bands of Nd-rich phase par-ticles form parallel to the advancing solidification plane-front.
关键词:
Ti-55 alloy
,
null
,
null
