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Abstract:
Functional
expressions of mε, mv and mF (they are respectively strain rate
sensitivity index under fixed strain ε, strain rate sensitivity index
under fixed forming velocity v and strain rate sensitivity index under
fixed load F) in plastic and superplastic deformation from the state
equation and the basidc mechanical theory are deduced. Furthermore,
experimental data of typical superplastic alloy ZnAI5 are consistent
with the theoretical value. Thus, the problem-why mε, mv and mF are
different with ε changing, even obtain abnormal result that the value of
mF is more than 1 and the value of mv is negative-is solved
theoretically, which is put forward experimentally. Then mechanical
essence of m value is revealed further.
Key words:
Superplasticity Plasticity Strain rate sensitivity index
CLC No: TH871
国家自然科学基金资助项目. Received 20000719,
received in revised form 20001118
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