sion of 47.5× 10.0× 0.3 mm3 were bent to a circular form with a radius of r= 10 mm or 20 mm and then fixed outside by a steel wire. The constrained specimen was then isothermally heated in a silicon oil bath at temperatures below 523 K or in a salt or lead bath above 523 K. As for a measurement of shape change with tensile mode, single crystals or polycrystalline plates of Cu-28.9 at% Zn-6.1 at% Al alloy with a dimension of about 13× 2.0× 0.2 mm3 were slightly loaded by a small tensile equipment in a bath as shown in Fig. 1, and measured the elongation during heating at various temperatures. Morphological and structural examinations were made on the specimens in the above experiments by optical and electron microscopy as well as electron diffraction. Thin specimens were prepared for transmission electron microscopy by jet polishing. A Hitachi HU-650 electron microscope was used at 650 kV.