An Investigation of the Mechanical Properties of Silicon Carbide and Sapphire Filaments

Tensile strength of directionally solidified chromia-doped sapphire

“…Ceramic single-crystal and eutectic fibers is one of the significant examples. [1][2][3][4][5][6][7][8] They can be fabricated systematically, even commercially, by DS with controlled composition, allowing important fundamental studies on the physical properties of materials.…”

“…[1][2][3][4][5][6]10 The addition of dopants to sapphire is known to change structural properties, 11,12 by the microscopic mechanisms of solution hardening. 13 Studies by Sayir et al 3 showed that enhanced high temperature (HT) strength is obtained in MgO-doped sapphire, while the most efficient dopant at room temperature (RT) is Ti 4+ .…”

Creep of directionally solidified alumina/YAG eutectic monofilaments

“…General Electric Inc. and MSNW Inc. showed very good creep behavior for several orientations of single crystal YAG up to 1700 • C. [17][18][19][20][21] Unfortunately, they also showed that single crystal fibers are limited by a low fracture toughness (K c ) and strength degradation at moderate temperatures caused by flaws that undergo slow crack growth. [22][23][24][25][26][27][28][29][30][31][32] In hopes of overcoming the shortcomings of both polycrystalline and single crystal fibers, two-phase single crystals structures (Directionally Solidified Eutectics [DSE]) have been explored because they should provide better strength, creep resistance, and toughness. The hypothesis here is that the tensile strength and toughness of a eutectic fiber may be increased due to the presence of a large number of interphase boundaries across the fiber cross-section (i.e., a fine transverse phase spacing).…”