Discerning size effect strengthening in ultrafine-grained Mg thin films

Microtensile experiments have been performed to elucidate the mechanical response of ultrafine-grained Mg thin films. Strengths of 160 MPa and elongations up to 8% were measured. Post-deformation electron microscopy indicates a lack of intragranular dislocation confinement. While strength does increase with decreasing grain size, the size effect for hexagonal Mg is not as strong as that reported for face-centered cubic metals. Strength appears to be governed by a lack of dislocation pile-up as well as texture and Peierls effects.