Requirements for achieving high-strain-rate superplasticity in cast aluminium alloys

Equal-channel angular (ECA) pressing has been used to introduce a very small grain size into a commercial cast Al-Mg-Li-Zr alloy. Tensile testing reveals the potential for achieving superplastic ductilities in this alloy at very -high strain rates (greater than 10-2s-1) but experiments show that this potential is realized only if a sufficiently high strain is introduced during the ECA pressing such that the microstructure is homogeneous and consists of an array of grains having large-angle grain boundaries.