Tensile tests were performed in the [100] direction, at 200 to 500K, on high-purity single crystals of the white phase. The samples had a low dislocation density. It was found that the stress-strain curves exhibited 2 yield points at temperatures below 300K. The first yield point phenomenon appeared when a sudden multiplication of mobile dislocations occurred due to the deformation. The second yield point phenomenon appeared when the dislocations which formed the cell structure became mobile and the cell structure disappeared. The activation energy of the second upper and lower yield stresses went through a transition at about 480K. The activation energy above this transition temperature was almost equal to the lattice diffusion energy. The activation energy below the transition temperature was equal to about half of the lattice diffusion activation energy, and was on the order that was expected for dislocation pipe diffusion.

Strain-Rate and Temperature Dependence of Plastic Deformation in White Tin Single Crystals. M.Nagasaka: Japanese Journal of Applied Physics - 1, 1999, 38[1A], 171-5