High strain rate superplasticity and its applications

摘要

Very high strain rate superplasticity (labelled as positive exponent superplasticity) was observed in near-nano scale aluminum alloys, which include the mechanically alloyed IN9021, IN9052, IN905XL alloys with very fine grained structures of 300 to 500 nm in sizes. In these alloys large elongations are obtained at extremely high strain rates between 10 and 1000 s~(-1) and in a high temperature range from 773 to 823 K. These results are applied to a specific example - the shaped charge -, and it is considered that the extraordinarily high strains undergone by the shaped charge jets can be explained by positive exponent superplasticity.