Growth directions in directionally solidified Al–Zn and Zn–Al alloys near eutectic composition

Growth directions and crystallographic orientations of solidification microstructures have been measured in Al–Zn alloy near the eutectic composition. Al dendrites in Al–92 wt.% Zn alloy were found to grow along the 〈1 1 0〉 directions while Zn dendrites in Al–96 and 98 wt.% Zn have 〈101¯0〉 trunks. In the lamellar eutectic, a crystallographic relationship has been found between the dense plane of each phase, i.e. {111}fcc‖{0001}hcp, and the dense directions, i.e. 〈110〉fcc‖〈12¯10〉hcp.