Rapid microcantilever preparation for conditional fracture toughness evaluation

The Ga + focused Ion Beam (FIB) or Xe + Plasma FIB (PFIB) procedure has enabled the ability to make specimens where mechanical tests in the microscale regime can be achieved with high precision. Nevertheless, milling times can be long and shape optimization can be arduous collectively limiting the ability to readily make a sufficient number of test samples. In this work, we present a sample preparation technique for microscale cantilever fabrication which streamlines the milling procedures by using combined electropolishing and FIB milling. Specifically, the procedure mitigates extensive undercutting requirements which reduces the fabrication time for the microcantilever to more than half that time as compared to direct milling methods from making similar geometries directly from the bulk material. This process is discussed along with specific aspects related to the sample alignment of the cantilever to specific fracture planes for single crystals. In addition, we comment on the applicability of this method to polycrystalline samples.