The influence of solidification conditions (temperature, cooling rate, pressure) on the sequence of phase transformations and the structure that forms during the solidification of three Al–Cu–Ni alloys with 10 at % Ni and 17. 5, 24, and 30 at % Cu is investigated. Under all the cooling conditions under study, the structure of the alloys is found to be two-level: it consists of massive primary dendrites based on Al–Ni intermetallics (first level) and eutectic structures with excess Al–Cu–based intermetallics (second level). The formation of such a structure is caused by the wide solidification temperature range of the alloys. A change in the cooling rate at atmospheric pressure is shown not to affect the sequence of phase formation, but it can be used to control the primary intermetallic crystal sizes. At the same time, a change in the solidification pressure shifts phase equilibria along temperature and concentration, which fundamentally changes the character of phase formation. In particular, an increase in the pressure affects the peritectic transformations L + Al3Ni2 L + Al3Ni and L + β-AlNi L + Al3Ni2 and expands the concentration range of the ternary τ-Al7Cu3Ni intermetallic compound and the homogeneity ranges of the AlNi and AlCu intermetallics.
Kamaeva et al. (Sat,) studied this question.