Crystallographic Information Framework

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Suggestion for new CIF data item

Status: Under review

My company writes HREBSD software which performs the analysis of high quality EBSD patterns to measure elastic strain levels and the effects of plastic strain.

One of the outputs we provide is an estimate of the geometrically nessary dislocation density. This calculation requires a knowledge of which slip systems are active in a particular phase.

I have been able to hard code slip systems for the most common symmetries (FCC, BCC , Hexagonal) and I have added in a few specific phases to cover for individual customer requests, but this is not a sustainable approach.

My solution is to try and create a data format to encode slip systems which I can then attach to a particular phase description - which brings me here.

I expect I wil have to code a bespoke file format in the short tomedium term, but I am hoping to move towards using the .CIF format for all aspects of phase information and the inclusion of slip system info would be a tremendous boon.

It is also worth noting that I could not find a data base of slips system information 

 

 

Contributed by Graham Meaden on 13 Aug 2020

 

Slip Systems

Definition:

 Each slip is defined by:-
A line direction
A slip plane normal
A burgers vector
These can all be defined with respect to the unit cell dimensions and crystal planes.
A slip system is defined by a crystal plane, a slip direction and a burgers vector length

Example:

For diamond (effectivly also for FCC) slip plane -> {111} slip direction - > <110> burgers vector -> a/2 <110> where a is the unit cell dimension. The example above gives families of planes and directions - I do not know if there are phases out there that only slip on a sub set of those families - perhaps it would be better to store the individual planes and direction combinations as follows:- Edges {-1,1,0} (1,1,1) {1,0,-1} (1,1,1) {0,-1,1} (1,1,1) {-1,-1,0} (1,-1,-1) {1,0,1} (1,-1,-1) {0,1,-1} (1,-1,-1) {1,1,0} (-1,1,-1) {-1,0,1} (-1,1,-1) {0,-1,-1} (-1,1,-1) {1,-1,0} (-1,-1,1) {-1,0,-1} (-1,-1,1) {0,1,1} (-1,-1,1) screw {1,1,0} (1,-1,-1) {1,0,1} (1,-1,-1) {0,1,1} (-1,1,-1) {-1,1,0} (1,1,1) {1,0,-1} (1,1,1) {0,-1,1} (1,1,1) along with a burgers vector length (a/2)

Category: Slips system

 

Any other attributes suggested by the submitter are listed here: