Improving ductility by increasing fraction of interfacial zone in low C steel/304 SS laminates

Superior mechanical properties and deformation mechanisms of heterogeneous laminates under dynamic shear loading

“…Based on the one-dimensional elastic stress wave theory, the shear stress and the shear displacement in the specimens under dynamic shear loading can be calculated as follows: Schematics of sample extraction for microstructural examination was also displayed in transmission electron microscope (TEM). The sample preparations for OM, SEM, and EBSD observations can be referred to [26]. In EBSD observation, the scanning step was set to be 100 nm.…”

“…While these two properties are mutually exclusive in general, i.e., high yield strength usually results in limited ductility. In the last two decades, several heterogeneous microstructures have been proposed to produce both high yield strength and large tensile ductility in metals and alloys, such as bimodal/multimodal structures [1,9], gradient structures [10][11][12][13], lamella structures [8,14,15], and bimetallic laminates [16][17][18][19][20][21][22][23][24][25][26]. These heterogeneous microstructures generally have various domains with different mechanical properties, and the plastic deformation incompatibility can occur among these domains [8,[27][28][29].…”

“…Thus, stress/strain partitioning and back stress hardening have been reported to play important roles in the plastic deformation of these heterogeneous microstructures [8,17,[27][28][29]. Among these heterogeneous microstructures, bimetallic laminates have great advantages for structural applications due to the fact that superior tensile properties can be achieved by regulating microstructural parameters, such as microstructures across the interface, hardness difference between plates, and interface spacing [16][17][18][19][20][21][22][23][24][25][26].…”

“…The mechanical properties and the deformation mechanisms in bimetallic laminates have been widely studied and well understood under quasi-static conditions [16][17][18][19][20][21][22][23][24][25][26], while their plastic deformation behaviors under high strain rates are still unclear until now. As we know, the flow and facture behavior of materials under impact loading should be dramatically different from that under quasi-static conditions since thermal softening induced by adiabatic heating, strain rate effect and inertia effect can significantly affect the plastic deformation and fracture mechanisms [30][31][32][33][34][35] [36][37][38][39][40][41][42][43].…”

“…In heterogeneous grain structure and gradient structure, the dynamic shear properties can be significantly improved by the stress/strain partitioning among different domains with various grain sizes and the back stress hardening [44][45][46], while no obvious interfaces exist in these heterogeneous microstructures. The interfaces have been reported to significantly strengthen and toughen bimetallic laminates under quasistatic conditions, the strain gradient and the pile-up of geometrically necessary dislocations (GNDs) near the interface zone have been found to play important roles in the strengthening and toughening [16,17,25,26]. While, how the interfaces affect the dynamic shear properties and the evolution of ASB in bimetallic laminates is still in vague.…”