Published online by Cambridge University Press: 18 December 2009
Introduction
The three main interfaces which are important in metallic systems are the solid–gas interface (the external surface), the interface between two crystals of the same phase which differ only in orientation (the grain boundary) and the interface between two different phases (the interphase boundary). The interphase boundary provides an almost infinite range of possibilities since in addition to the possible difference of orientation of the two crystals, the crystals can also differ in crystal structure, lattice parameter and in composition. In this almost infinite array of possible structures and thus properties two limiting conditions can be recognised. In one case where the interface is formed, as it often is in metallic systems, by precipitation of a second phase within a primary crystal structure then a particular orientation relationship develops between the phases. This produces an interface with a close atomic fit which minimises the interfacial energy (see §2.2.2 and Doherty (1982)). This, in turn, can introduce difficulties for interfacial mobility in that growth ledges may be needed, see §1.3. The opposite extreme occurs when the two phases have no orientation relationship with each other. As a result their interface will be a high energy, incoherent one that usually provides no particular crystallographic barrier to mobility. Examples of this type of incoherent interface arise when the two phases come in contact by growth processes rather than by nucleation.
To save this book to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.