Novel ceramic matrix composites with tungsten and molybdenum fiber reinforcement

Abstract

Ceramic matrix composites usually utilize carbon or ceramic fibers as reinforcements. However, such fibers often expose a low ductility during failure. In this work, we follow the idea of a reinforcement concept of a ceramic matrix reinforced by refractory metal fibers to reach pseudo ductile behavior during failure. Tungsten and molybdenum fibers were chosen as reinforcement in SiCN ceramic matrix composites manufactured by polymer infiltration and pyrolysis process. The composites were investigated with respect to microstructure, flexural-and tensile strength. The single fiber strengths for both tungsten and molybdenum were investigated and compared to the strength of the composites. Tensile strengths of 206 and 156 MPa as well as bending strengths of 427 and 312 MPa were achieved for W/SiCN and Mo/SiCN composites, respectively. The W fiber became brittle across the entire cross section, while the Mo fiber showed a superficial, brittle reaction zone but kept ductile on the inside.

Prevention of SiC‐fiber decomposition via integration of a buffer layer in ZrB2‐based ultra‐high temperature ceramics

“…30,50 Experiments with Mo-fibers embedded in a SiCN matrix, manufactured by polymer infiltration and subsequent pyrolysis, revealed the formation of Mo 2 C and Mo 5 Si 3 . 51 However, such Mo-rich phases were not observed in any of our three buffer-layer systems. All hot-pressed composites were fully dense, as shown in Figure 3B-D.…”

“…The addition of MoSi 2 compensates the high shrinkage of the precursor during pyrolysis due to catalytic effects on the crosslinking reaction of the polymer with residual carbon or nitrogen in the system, in turn leading to the formation of secondary phases such as Mo 5 Si 3 , Mo 2 C, β‐SiC, and Si 3 N 4 30,50 . Experiments with Mo‐fibers embedded in a SiCN matrix, manufactured by polymer infiltration and subsequent pyrolysis, revealed the formation of Mo 2 C and Mo 5 Si 3 51 . However, such Mo‐rich phases were not observed in any of our three buffer‐layer systems.…”

Synthesis and characterization of engineered PEEK‐based composites for enhanced tribological and mechanical performance

“…40 Moreover, Mo fibers have been used in ceramics matrix for reinforcement. 41 As discussed earlier, biopolymers matrices filled with ceramic fillers is widely used in bone tissue engineering. 42 Xonotlite is a crystalline, calcium silicate hydrate Ca 6 Si 6 O 17 (OH) mineral.…”

“…Mo has also been explored as corrosion inhibitor in chitosan matrix 40 . Moreover, Mo fibers have been used in ceramics matrix for reinforcement 41 …”

Insight into the Microstructure and Tensile Behavior of the W–Cu Composite Reinforced with Tungsten Fibers and Particulates

“…Therefore, it has become increasingly attractive to be used in high-performance composites. [5][6][7][8] More fortunately, the principle concept of "tungsten fiber (W f )-reinforced W composites overcome the brittleness of W" has been demonstrated [9] by the toughening effect on the composite consisting of a single W f embedded in the tungsten matrix [10] and the pseudo-ductile behavior in pushout experiments and ANSYS simulation. [11] On the other hand, it should be pointed out that W-Cu composites benefiting from the high strength of W and high conductivity of Cu are candidate heat sink materials for highly heat-loaded plasma-facing components.…”