Relating Grain Boundary Structure to Superplastic Deformation

1996 ◽  
Vol 243-245 ◽  
pp. 99-108 ◽  
Author(s):  
Richard I. Todd
1990 ◽  
Vol 196 ◽  
Author(s):  
H. J. Frost ◽  
R. Raj

ABSTRACTA model is presented to explain the grain growth that is often observed during superplastic deformation. The atomic structure of grain boundaries leads to a coupling between boundary sliding and boundary migration. There is a similar coupling between the absorption or emission of vacancies from a boundary and boundary migration. Because of these couplings, the grain boundary sliding and diffusional flow of superplastic deformation produce extensive boundary migration. We propose that this forced migration leads to random changes in the sizes of grains, and that this evolution of the grain size distribution leads to grain growth.


Author(s):  
P. Humble

There has been sustained interest over the last few years into both the intrinsic (primary and secondary) structure of grain boundaries and the extrinsic structure e.g. the interaction of matrix dislocations with the boundary. Most of the investigations carried out by electron microscopy have involved only the use of information contained in the transmitted image (bright field, dark field, weak beam etc.). Whilst these imaging modes are appropriate to the cases of relatively coarse intrinsic or extrinsic grain boundary dislocation structures, it is apparent that in principle (and indeed in practice, e.g. (1)-(3)) the diffraction patterns from the boundary can give extra independent information about the fine scale periodic intrinsic structure of the boundary.In this paper I shall describe one investigation into each type of structure using the appropriate method of obtaining the necessary information which has been carried out recently at Tribophysics.


Author(s):  
Brian Ralph ◽  
Barlow Claire ◽  
Nicola Ecob

This brief review seeks to summarize some of the main property changes which may be induced by altering the grain structure of materials. Where appropriate an interpretation is given of these changes in terms of current theories of grain boundary structure, and some examples from current studies are presented at the end of this paper.


1975 ◽  
Vol 36 (C4) ◽  
pp. C4-17-C4-22 ◽  
Author(s):  
R. W. BALLUFFI ◽  
P. J. GOODHEW ◽  
T. Y. TAN ◽  
W. R. WAGNER

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