Evaluation of structural and mechanical strength of symmetric tilt interface in W/Fe composite laminate using molecular dynamics

In this work, a tungsten (W)/iron (Fe) composite laminate is constructed by joining two constituents W and Fe according to the symmetric tilt interface relationship. The performance of the newly built W/Fe symmetric tilt interfaces is evaluated by interface energy, tensile stress-strain relationship, and strength and then compared with semi-coherent W/Fe boundaries and W and Fe symmetric tilt grain boundaries. The results show that even though most W/Fe symmetric tilt interfaces have very high interface energy, some have interface energy comparable to those of semi-coherent W/Fe boundaries and W and Fe symmetric tilt grain boundaries, and thus should be considered for W/Fe composites. The mechanical properties for tensile deformation parallel to the interface of these stable W/Fe symmetric tilt interfaces outperform the estimated values from composite theory and even those of semi-coherent W/Fe boundaries. Our findings suggest that the symmetric tilt interfaces not only play an important role in the interface strength of W/Fe composite laminate, but also should be incorporated into future designs of W/Fe or other composites to circumvent the lattice, thermal, and mechanical mismatches between heterogeneous constituents.