How Do You Calculate Yield Stress in an Aluminium Single Crystal Alloy?

[edcurrymuncher]

Hey, this was the question could someone please help?

"An aluminium single crystal alloy aircraft component is oriented such that a tensile stress is applied along a [102] direction. If slip in this material occurs on a (111) plane
and in a [101] direction, compute the yield stress at which the crystal yields if its critical resolved shear stress is 3.42MPa."

Thanks :)

 

[jk60422]

Suggest you do your own Schmid's law homework.

PS the [101] direction isn't a valid direction in the (111) plane.

 

[jstad]

I am no authority on the subject but I recently did a problem very similar to the one you're working on. And I believe the poster above me is correct in their assertion. In my problem, the applied load was [120], slip plane (111) and slip direction [110].

Something helpful (which I learned from my professors) is to draw the cubic cell with the indicated plane and directions. This will help you get a feel of what \phi and \lambda look like. In addition to load and slip directions, you will also need to determine the direction perpendicular to the slip plane.

The key, however, is to use the dot product to find cos\phi and cos\lambda. In order to do this you will need to treat the three key directions as vectors.

Hopefully this was of some help to you.