The Phenomenon of Structural Superplasticity in Oxygen Ceramics

1994 ◽  
Vol 170-172 ◽  
pp. 397-402 ◽  
Author(s):  
N.G. Zaripov ◽  
O.M. Kolnogorov ◽  
L.V. Petrova
Keyword(s):  
Structural Superplasticity

Structural Superplasticity — Experimental

1980 ◽  
pp. 43-132
Author(s):  
Kuppuswamy Anantha Padmanabhan ◽  
Graeme John Davies
Keyword(s):  
Structural Superplasticity

Universality of the Phenomenology of Structural Superplasticity

2016 ◽  
Vol 838-839 ◽  
pp. 84-88
Author(s):  
Sriharsha Sripathi ◽  
K.A. Padmanabhan
Keyword(s):  
Strain Rate ◽  
Boltzmann Constant ◽  
Limited Data ◽  
General Shape ◽  
Free Energy Of Activation ◽  
Structural Superplasticity ◽  
Superplastic Alloy ◽  
Controlling Mechanism ◽  
Absolute Test ◽  
Using Data

The equation σ=Kέm, where σ is the applied stress, έ is the strain rate, K and m are material constants that depend on stress / strain rate, temperature and grain size is often used to describe structural superplasticity. The general shape of the logσ-logέ curve is sigmoidal. Based on limited data, it was suggested by us earlier that a universal σ-έ curve could exist in a properly normalized space. έ and m are normalized with respect to έopt and mmax, the strain rate at which m is a maximum and the maximum m value respectively. Here a multi-dimensional relationship involving σ/σopt-έ/έopt-m/mmax-ΔF0/kT-η/ηopt is developed; σopt corresponds to έopt, ΔF0 is the free energy of activation for the rate controlling mechanism, k the Boltzmann constant, T the absolute test temperature, η the (apparent) viscosity of the superplastic alloy and ηopt is the viscosity of the same alloy for m=1 in a dimensionless σ-έ space. Using data concerning many systems, the phenomenology of structural superplasticity in all classes of materials is shown to be unique.

Comments on theories of structural superplasticity

1978 ◽  
Vol 36 (1) ◽  
pp. 27-33 ◽  
Author(s):  
R.C. Gifkins ◽  
T.G. Langdon
Keyword(s):  
Structural Superplasticity
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