Recent experiments and simulations have demonstrated that particle-covered fluid/fluid interfaces can exist in stable
nonspherical shapes as a result of the steric jamming of the interfacially trapped particles. The jamming confers the
interface with solidlike properties. We provide an experimental and theoretical characterization of the mechanical
properties of these armored objects, with attention given to the two-dimensional granular state of the interface. Small
inhomogeneous stresses produce a plastic response, while homogeneous stresses produce a weak elastic response.
Shear-driven particle-scale rearrangements explain the basic threshold needed to obtain the near-perfect plastic deformation
that is observed. Furthermore, the inhomogeneous stress state of the interface is exhibited experimentally by using
surfactants to destabilize the particles on the surface. Since the interfacially trapped particles retain their individual
characteristics, armored interfaces can be recognized as a kind of composite material with distinct chemical,structural,