Advances in In situ microfracture experimentation techniques: A case of nanoscale metal-metal multilayered materials

Plasticity and fracture of materials at the nanoscale levels can deviate significantly from the same phenomena in bulk properties, which may have important implications if they are to be used in real-world engineering systems. Nanoscale metal-metal multilayered materials provide a model material system platform to understand plasticity and fracture based on dislocation interactions with microstructural features. Recently, there is a growing trend to understand the fracture of multilayered materials to see the interactions between the crack and multilayered interface through novel experimentation techniques. In this review, we will introduce the rationale, the current microfracture methods to test and analyze the multilayer fracture behavior and the challenges faced in performing them. Four examples of in situ fracture techniques are highlighted in this work through tensile testing of film on a substrate: microfracture clamped beam bending technique across the multilayers and delamination along the multilayered interface.