K.Y.Cheng
,
D.H.Kim
,
Y.S.Yoo
,
C.Y.Jo
,
T.Jin
,
Z.Q.Hu
材料科学技术（英）
Microstructural stability of a nickel base single crystal alloy DD8 has been investigated. Standard heat treated specimen showed good microstructural stability at 950℃. While under the as-cast condition, a kind of rod-like phase precipitated in the interdendritic region of as-cast specimen during thermal exposure. The phase, which has bcc structure, was enriched with Cr. Thermo-calc also predicted precipitation of a bcc phase at around 950℃. The Cr-rich bcc phase was considered as α-Cr and formed due to the segregation of Cr under the as-cast condition.
关键词:
DD-8
,
null
,
null
,
null
S.M.Seo
,
I.S.Kim
,
J.H.Lee
,
C.Y.Jo
,
H.Miyahara
,
K.Ogi
材料科学技术（英）
Microstructural evolution during directional solidification (DS) of Ni-base superalloy IN792+Hf has been investigated with an emphasis on the γ′ precipitates and MC-type carbides. The quantitative image analyses revealed that the increase in the solidification rate up to 100 μm/s at constant thermal gradient of 178 K/cm resulted in a fine and uniform distribution of γ′ precipitates. The relationship between the as-cast γ′ size and cooling rate was also determined for DS IN792+Hf. In the mean time, the MC carbide size was found to be dependent both on the solidification rate and the S/L interface morphology while the area fraction of MC carbide was significantly influenced by the S/L interface morphology.
关键词:
IN792
,
null
,
null
,
null
