抄録
An electron microscope study was made on the wedge-shaped martensite β″ in Cu–24.5 wt%Sn alloy, which was produced by quenching into water and then dipping in liquid nitrogen.
From the diffraction patterns it is found that the β″ martensite has a close-packed orthorhombic structure of AB′ stacking. Its electron microstructure consists of lamellae parallel to the (121) plane, and spots due to the (121) twin are observed in the diffraction pattern. From these facts it is concluded that the β″ martensite has twin faults due to the transformation. Moreover there are finer striations within them. These striations are thought to be contrasts of stacking faults parallel to (1\bar21) planes.
The crystal orientation relationships between the β″ martensite and the parent phase β1 are
(001)β″⁄⁄(110)β1 and [\bar210]β″⁄⁄[\bar11\bar1]β1.
