Investigation of Compression Deformation Behavior and Microstructure Evolution of NiAl-Cr (Mo)-Hf Alloy at Elevated Temperature

Abstract:

NiAl-based alloy is a promising material applied in the fields of aeronautic and astronautic instruments. In the paper the compression deformation behavior and microstructure evolution of NiAl-Cr(Mo)-Hf alloy at elevated temperature were studied. The results demonstrate that the alloy behaves good formability in the temperature ranging from 1320°C to 1360°C, in which the maximum initial strain rate is about 8.3×10-4s-1 and the maximum deformation resistance is lower than 40MPa. During compression at temperature between 1250°C and 1300°C the flow stress increased sharply with the increasing of the deformation degree. When compression deformation at 1320°C~1360°C, the flow stress decreased obviously and the flow stress decreased slightly after reached the maximum value. By analyzing the microstructure evolution during compression it can be concluded that as-casting microstructure was improved in deformation. The grains were refined and the brittle phases of lamellar Cr(Mo) existing at NiAl matrix were broken. The porosities in as-casting material were eliminated during compression and the density of the material increased. The fracture toughness of the alloy increased from 6.4MPa·m1/2 to 9.8MPa·m1/2 after compression.

• Periodical: Materials Science Forum (Volumes 551-552)
• Pages: 457-461
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.551-552.457
• Online since: July 2007
• Authors: Guo Qing Chen, S.H. Ji, Wen Long Zhou, C.W. Wu, Jian Ting Guo, Z.H. Huang
• Keywords: Compression Deformation, Fracture Toughness, Microstructure, NiAl Based Alloys

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