Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Elastic Anisotropy vs Crystal packing

  1. Mar 3, 2008 #1
    I have calculated the dependence of (1/s11) ie. single-crystal young's modulus on crystallographic direction for an inorganic crystal.

    I've noticed that certain peaks correspond to closely-packed planes eg. a psedo-hexagonal arrangement is seen in directions where the peaks (ie. local maxima) for (1/s11) occur.

    I wonder if one can immediately conclude that the strength of the bonding and/or peak in the young's modulus is due to the way the atoms are packed. Any comments?
  2. jcsd
  3. Mar 3, 2008 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    According to Hertzberg's Deformation and Fracture Mechanics of Engineering Materials, it is not typically the case that close-packed directions are stiffest. In fcc Al and Au and in bcc Fe, the <111> direction is stiffest. In bcc Mo, the <100> direction is stiffest. There doesn't seem to be a pattern.
  4. Mar 3, 2008 #3
    ok, great, thank you so much, that settles a lot of things.

    I should then say that (1) some directions are stiffer than others (2) these directions happen to have close-packing.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Elastic Anisotropy vs Crystal packing
  1. Magnetic anisotropy (Replies: 1)