Title of article :
Effect of withdrawal rate on the microstructure of directionally solidified NiAl–Cr(Mo) hypereutectic alloy
Author/Authors :
Shang، نويسنده , , Zhao and Shen، نويسنده , , Jun and Zhang، نويسنده , , Jianfei and Wang، نويسنده , , Lei and Fu، نويسنده , , Hengzhi، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2012
Pages :
7
From page :
99
To page :
105
Abstract :
Solidification microstructure and growth interface morphology of directionally solidified Ni–31Al–32Cr–6Mo(at.%) hypereutectic alloy were studied. The experiments were carried out at higher temperature gradient of about 250 K cm−1 with different withdrawal rates of 4–500 μm s−1. When the withdrawal rate was less than 50 μm s−1, the primary Cr(Mo) dendrites were gradually eliminated through competitive growth between the primary phase and the eutectic phase. When the withdrawal rate exceeded 100 μm s−1, no primary phase formed, eutectic phase grew directly. Fully eutectic microstructures with lamellar morphology were observed at all withdrawal rates. With increasing withdrawal rate V, the growth interface changed from planar to cellular and then dendritic, the solidification microstructure also transformed from planar eutectic to two-phase cellular eutectic and dendritic eutectic. The microstructure was refined and the eutectic interlamellar spacing λ decreased according to the relationship of λ = 4.82V−0.42. Compared to the alloy at eutectic composition, the volume fraction of Cr(Mo) strengthening phase was increased obviously.
Keywords :
D. Microstructure , G. Aero-engine components , A. Nickel aluminides , based on NiAl , A. Composites , C. Crystal growth
Journal title :
Intermetallics
Serial Year :
2012
Journal title :
Intermetallics
Record number :
1505250
Link To Document :
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