STRUCTURE AND ENERGY OF (110) TWIST BOUNDARIES IN THE AG NI SYSTEM/

Low-energy (110) twist boundaries have been studied in the Ag/Ni syste m. Four low-energy orientations were observed in the experiments using the particle rotation method (PRM) with (110)Ag crystallites sintered on the (110) surface of a single crystal Ni substrate. These are char acterized by twist angles of 0, 35, 55 and 70-degrees, measured betwee n the two close-packed direction of the crystals at the boundary. The determination of the orientation of the samples was made by transmissi on electron microscopy. The reorientation of the particles was achieve d in two ways: continuous rotation. and twinning. In samples with init ial twist angles of 3, 35, and 49-degrees, a progressive rotation of t he particles was observed. The silver particles in the sample with 70 initial twist were reoriented to 0-degrees by the nucleation and growt h of twins which had parallel crystallographic directions with the Ni substrate. Samples with initial twist angles of 58 and 65 showed both types of reorientation. While the particles underwent a continuous rot ation, twins nucleated and grew in the particles. The results of the e xperiments are compared with calculations with the embedded-atom metho d and with geometrical models of interfaces.