Bioceramics in Composites

The main reason for forming composites is to improve the mechanical properties, most often toughness, above that of the stand-alone ceramic. For bioceramic composites we often are trying to increase Kic and decrease T. 

Assuming that the fibers are aligned in the direction of the applied load, and that there is good adhesion with the matrix such that the elastic strains are equal in both components, we can write 

The subscripts c, f, and m refer to the composite, fiber, and matrix, respectively, and V is the volume fraction of each phase. If we assume 45 vol% of steel fibers and Of = 530 MPa and Om = 42 MPa, then Oc = 262 MPa. This value, which is close to experimentally measured values, represents a significant strengthening above that of the glass alone. 

One of the potential problems associated with forming composites is that of mismatch in a between the two ----------- 

For reinforcing fibers for which the difference in a with the glass phase is even greater than that with steel, e.g., Ti, it is necessary to change the composition of the glass to lower its a. -------- 

---