Continuous fiber-reinforced tools for downhole use

Continuous fiber-reinforced hard composites may be useful in mitigating crack propagation in downhole tools. In some instances, a wellbore tool may be formed at least in part by a continuous fiber-reinforced hard composite portion. The continuous fiber-reinforced hard composite portion includes a binder material continuous phase with reinforcing particles and continuous fibers contained therein, wherein the continuous fibers have an aspect ratio at least 15 times greater than a critical aspect ratio (Ac). The critical aspect ratio can be determined using the equation Ac=σf/(2τc), σf is an ultimate tensile strength of the continuous fibers, and τC is a lower of (1) an interfacial shear bond strength between the continuous fibers and the binder material and (2) a yield stress of the binder material.