Plastic deformation of polycrystalline alumina introduced by scaled-down drop-weight impacts

•Samples of fully dense, pure alumina with an equiaxial grain structure were prepared.•A demonstration of the damage introduced during low load, low velocity, blunt impacts is provided.•The generation of a well-formed and measurable impression is observed for the first time.•Fracturing is shown to play an insignificant role in the process.•Plastic deformation around and beneath the residual cavity is proposed as the core contributor.

We present our findings after scaled-down drop-weight tests, performed under relatively low loading conditions and employing a small-scale spherical indenter as a projectile, to boost the strain rate and energy density of the impact, resulted in the generation of a cavity of measurable depth on the surface of a pure, fully dense, alumina ceramic. We demonstrate that activated dislocations are a main contributor in the formation of the residual impression with an estimated maximum density of ~4.02×1014 m−2.