There are many Zr particles in as-cast NiAl-33.5Cr-0.5Zr (at. pct) alloy, which usually exist at the edge of eutectic of β-NiAl and α-Cr. After air and furnace cooling solution treatments, for 14000C, 2 h and 1450℃, 1 h, pure Zr phase remains in the furnace cooling (F.C.) state alloys and Ni2AlZr phase forms in the air cooling (AC.) state alloys. During solution treatment at 14500C, bulk and "fish bone"shape Zr-rich phases form respectively in F.C. and AC. state alloys. A ’river’?shape Ni2AlZr phase forms after 14500C for lh F.C. and 8500C for 12 h, F.C.. The alloy has less pure Zr and Ni2AlZr phase after 14000C with both air and furnace cooling followed by 8500C and 9500C for 12 h, F.C. aging treatments, respectively. Additionally, there is a ternary eutectic of NiAIZr and a phase enriched Zr and Cr forms at the edge of the eutectic of β-NiAl and α-Cr in the alloy treated at 14000C, 2 h, F.C. and 9500C, 12 h, F.C.
Hui LI, sJianting GUQ, Wanhui LAI and Shuhe WANG Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
The microstructure and creep behavior of a DS NiAI-Fe(Nb) multiphase intermetallic alloy have been investigated. This alloyexhibits dendritic structure, in which dendritic arm is β-(Ni,Fe)(Fe,Al) phase surrounded by interdendritic region of γ'/γ phase.The results of the creep test indicated that all of the creep curves have similar characteristic, which is a short primary creepstage and a dominant steady state creep stage, and the creep strain ranges from 18% to 52%. The apparent stress exponentand the apparent activation energy were analyzed and discussed. The mechanism of the creep deformation was also analyzedby the observation of TEM.
Yihui QI, Jianting GUO and Chuanyong GUIDepartment of Superalloys, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
