Observations of twinning in alpha plutonium by transmission electron microscopy

Twins have been observed in monoclinic alpha-phase plutonium using Transmission Electron Microscopy (TEM). These twins may be deformation twins or growth twins but are most likely growth twins as the sample was prepared by vapor to solid sputter deposition. Crystallographic analysis of electron diffraction data indicates that the composition or twin plane is the (201). This was confirmed using stereographic projection analyses as well as by comparisons of experimentally determined diffraction patterns with computer generated patterns. A theoretical deformation twinning system for alpha plutonium incorporating the (201) as the twin plane has not previously been predicted. Further work is necessary to uniquely identify the complete twinning system for either annealing/growth or deformation twin formation in alpha plutonium. (orig.)