Abstract
Dislocation etch pits formed by Young’s etchants on (111) surfaces of as-grown Cu and Cu–Al dilute alloy crystals have been observed.
Triangular etch pits of which contrasts were classified into three kinds, dark, light and mixed, were observed in Cu crystals by an optical microscope of low magnification. The forms of these pits were examined in detail with an electron microscope. The dark etch pits were point-bottomed pyramids having sides with inclination angle larger than 0.122 rad, while the light ones took three different forms of shallow pyramids. Mixed etch pits were composed of dark (deep) and light (shallow) parts and moreover they took three different forms. The etch pits of Cu-0.1 at%Al alloy crystals were similar in morphology to those of Cu crystals. However, most of the etch pits of Cu-1.0∼2.5 at%Al alloy crystals were dark or light ones.
On the other hand, with the addition of Al, the etch pits became rounded and their size and slope became smaller. The effect of Al is discussed on the basis of the two-dimensional nucleation theory for the formation of dislocation etch pits.
