Gregor,
Research into all of this can be pretty fun, huh? And exhausting.
What you are looking for or have found (in terms of lattice structure for metals) is:
Hexagonal Close Packed
Face-Centered Cubic (sometimes called Cubic Close Packed)
Body Centered Cubic
I did a quick search and found this site which may help a little:
http://www.chemistry.ohio-state.edu/...754/str_cp.htm
You'll have to scroll down to nearly the bottom to see the table of elements (more common elements, not inclusive). From memory, Be (beryllium), when it oxidizes is highly TOXIC. Similar with Cadmium. Out of the list for HCP, magnesium, zinc, and titanium would be "the safer" metals to work with. Magnesium and Zinc oxidize very easily, so titanium may be the best to "work with".
Of course, remember that nearly all "metals" are alloys. Metallurgically speaking, it is nearly impossible to have a "pure" metal. Impurities and/or alloying elements change the structure and properties (physical, mechanical, etc.). Surely you can combine this with the torsion research you're doing...
Hope this helps, sorry if redundant.
Art