In situ electron irradiations at 300 and 1000 kV have been performed at 100 and 300 K on Ni2Al3 for comparison with its response under ion irradiation. In addition, the behavior of Ni2Al3 will be compared to that of NiAl3 reported previously. Thin multilayered films of alternating nickel and aluminum were electron beam deposited onto a NaCl substrate. The substrate was dissolved in deionized water and the Ni/Al film was mounted on 3 mm diam grids. The films were vacuum annealed for 1—2 h at 623 K to allow interdiffusion between the layers. Electron diffraction indicated that the films were fine-grained (∼20 nm diam) Ni2Al3, which is the prototype for the hexagonal D513 structure. No appreciable amount of other phases was detected.
The specimens were irradiated with 1000 kV electrons in a Hitachi HU-1000B or with 200—300 kV electrons in Philips EM430 and CM30 microscopes. All three microscopes are equipped for nominal room temperature or low temperature (∼100 K) irradiations.