Pore structure and compression behavior of porous TiAl alloys by freeze casting. (May 2020)

• Record Type: Journal Article
• Authors: Wang, Q.B.; Hou, Z.P.; Zhang, S.Z.; Feng, H.; Zhang, C.J.; Han, J.C.; Zhang, W.G.; Zhao, R.T.
• Is Part Of: Vacuum. Volume 175(2020)
• Publication Date: 2020-05
• Subjects: Porous TiAl alloys -- Freeze casting -- Structure -- Compression properties; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2020.109254
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: In this work, lamellar-like and spherical-like porous TiAl alloys have been fabricated by freeze casting using different slurries, and their compression behaviors have been investigated also. The lamellar-like porous alloy with a relative density of 0.34 exhibits a good homogeneous lamellar porous structure after removing unidirectional ice dendrites. The noticeable pores on the lamellar surface are attributed to the dehydrogenation of TiH2 and Kirkendall effect. Besides, the spherical-like porous alloy with a relative density of 0.24 exhibits uniform and well-defined spherical-like architecture. Compression tests show that the spherical-like porous alloy has better compression property than the lamellar-like porous alloy. The peak compression stress of the lamellar-like porous alloy reaches 60 MPa, whereas the stress fluctuated greatly with the increase of strain. Nevertheless, the spherical-like porous alloy shows a steady compression plateau stress of approximately 46 MPa and absorption energy per unit volume of 27.6 × 10 6 J/m 3 . Highlights: The lamellar-like and spherical-like porous TiAl green bodies have been fabricated by freeze casting using different slurries in this study. The lamellar-like porous alloy exhibits a good homogeneous lamellar porous structure after removing unidirectional ice dendrites. The spherical-like porous TiAl alloy fabricated has both high compression strength and high absorption energy per unit volume.