schmid factor calculation for different slip system in hcp crystals

[Peyman Ahmadian]

Dear all

i want to calculate schmid factor for different slip system (basal <11-20>{0001}, prismatic <11-20>{10-10}, pyramidal <11-20>{10-11} and pyramidal <11-23>{11-22})  in alpha phase with HCP structure in Ti64 alloy. firstly symmetry has been omitted. the important issue is that Ti64 consist 2 phase : 1- dominant alpha phase (HCP), 2- retained beta phase (BCC). beta phase has been ignored. and i am going to calculate schmid factor for different slip system in alpha phase. i study guideline in: https://mtex-toolbox.github.io/files/doc/PlasticDeformation.html#13 but i have some question:

1- question 1:

grains = calcGrains(ebsd);

plot(ebsd,ebsd.orientations)
hold on
plot(grains.boundary)
hold off
sS = slipSystem.fcc(ebsd.CS)
sS = sS.symmetrise;

1-1 i think it is necessary to change slipSystem.fcc(ebsd.CS) command to slipSystem.hcp(ebsd.CS) because alpha phase has hcp structure
but there is an error in running which tells: 

Warning: Maybe I should collect here all slipSystems below 
> In slipSystem.slipSystem>slipSystem.hcp at 122 
Error in slipSystem.slipSystem>slipSystem.hcp (line 122)
       warning('Maybe I should collect here all slipSystems below');      

Error using slipSystem.hcp
Output argument "sS" (and maybe others) not assigned during call to "M:\MTEX\mtex-4.5.0\geometry\@slipSystem\slipSystem.m>slipSystem.hcp".

when i use slipSystem.fcc(ebsd.CS) command, the output is:

sS = slipSystem (show methods, plot)
 mineral: Titanium (6/mmm, X||a*, Y||b, Z||c)
 CRSS: 1
 size: 1 x 1
   U   V   T   W | H   K   I   L
  -1   2  -1  -3   1   1  -2   1

is it true to use slipSystem.fcc(ebsd.CS) command in titanium with hcp structure?

2- question 2: there is an other error for running this command : sSLocal = grains.meanOrientation * sS

Error using phaseList/checkSinglePhase (line 282)
This operatorion is only permitted for a single phase! Please see modify EBSD data  for how to restrict EBSD data to a single phase.

Error in phaseList/get.CS (line 154)
      id = checkSinglePhase(pL);

how can i solve this error for Ti64 alloy which has two phase?

3- question 3: is it true procedure for schmid factor calculation in titanium?



best regards

[ruediger Kilian]

Hi Peyman,
1) you can define a slipsystem yourself e.g.
sS = symmetrise(slipSystem(Miller(1,-2,1,0,cs,'uvw'), Miller(1,0,-1,0,cs,'hkl'),1))
just make sure the slip direction is in the plane.

2) supply the phase name e.g. grains(’TitaniumPhaseXY’).meanOrientation
Make sure you set up the phase names correctly and that one phase name is not a subset of the other phase name [not titanium and titaniumXy but rather titaniumXY and titaniumYX], have a look at the answer I gave you on this topic in mid April)

3) I’m sorry, I fear I don’t understand this question.

Hope this helps.
Cheers,
Rüdiger

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[grandr...@gmail.com]

As an alternative, the gist at https://gist.github.com/jhiscocks/6912714e30721908f213887d50341158#file-schmidr2-m  may help. It's set up for magnesium but they are both HCP which may simplify matters.  Of course you will have to customize the slip systems for titanium.

Jessica