Pore structure and compression behavior of porous TiAl alloys by freeze casting

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 × 106 J/m3.