In situ uniaxial mechanical testing of small scale materials - A review

Materials at the micrometer and submicrometer scale exhibit mechanical properties that are substantially different from bulk materials. With the increasing miniaturization ofdevices, an accurate characterization of micro/nanoscale materials is necessary to ensuretheir reliability and performance. Precise characterization is also essential for a fundamental understanding of mechanisms that govern size dependent material responses. In thispaper we review methods for uniaxial mechanical testing, which directly provides mechanical properties without an apriori model, for micro/nanoscale materials with an emphasis onin situ testing. We outline the challenges involved in imposing pure uniaxial deformationon micro/nanoscale specimens and detail strategies (self aligning mechanisms, for example) that ensure a uniform stress state in the specimens, a critical criterion for uniaxial test.