display pole figure plots with RD on top and ND west
Slip in Body Centered Cubic Materials
In the following we consider crystallographic slip in bcc materials
under plane strain
The orientation dependence of the Taylor factor
For a family of slip systems sS the Taylor factor M describes the total amount of slip activity that is required to deform a crystal in orientation ori according to strain epsilon. In MTEX this can be computed by the command calcTaylor.
When called without specifying an orientation the command calcTaylor computes the Taylor factor M as well as the spin tensors W as orientation dependent functions, which can be easily visualized and analyzed.
The following code reproduces Fig. 5 of the paper of Bunge, H. J. (1970). Some applications of the Taylor theory of polycrystal plasticity. Kristall Und Technik, 5(1), 145-175. http://doi.org/10.1002/crat.19700050112
The orientation dependence of the spin
The norm of the spin tensor is exactly the angle of misorientation a crystal with the corresponding orientation experiences according to Taylor theory. Compare Fig. 8 of the above paper
Display the crystallographic spin in sigma sections
Identification of the most active slip directions
Next we consider a real world data set
and apply the Taylor model to each grain of our data set
plot the most active slip directions observe that they point all towards the lower hemisphere - why? they do change if q is changed