The properties of the semi-solid region in solidifying alloys is significant in determining the extent of defect development.

The Mohr-Coulomb yield criterion will be examined to determine its suitability in characterising the behaviour of semi-solid materials; and the shear strength, in particularly the coherency point, of semi-solid Al alloys will be examined to compare results with other testing methods.

A shear cell will be used to test the shear strengths of various Al semi-solid alloys under different solidification conditions and for a variety of different morphologies.