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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 1999, Vol. 20 ›› Issue (1): 30-33.

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MICROSTRUCTURE AND PHASE TRANSFORMATION OF THE Ni 30Al 1Hf ALLOY

Xing Zhanping, Han Yafang, Yan Minggao   

  1. First Laboratory, Institute of Aeronautical Materials, Beijing, 100095
  • Received:1998-03-26 Revised:1998-04-16 Online:1999-02-25 Published:1999-02-25

Abstract:

NiAl based two phase (β+γ) alloy Ni 30Al 1Hf was prepared by a directionally solidified method. It was found that the microstructure of the alloy was composed of β NiAl dendrites surrounded by interdendritic γ phases, There is an orientation relationship between β and γ phases in the as cast state. Homogenization at 1280℃/6h followed by air cooling or oil quenching resulted in the β NiAl phases in the two alloys mostly transformed to NiAl martensites . In the meantime, the volume percent of the γ Ni3Al phases decreased with increased cooling rate. After tensile testing at 900℃, all of the martensites disappeared, while γ precipitates were formed in the β NiAl phases.

Key words: NiAl, two-phase alloys, micr ostr uctur e, phase transformations

CLC Number: