1996 Volume 36 Issue 3 Pages 317-323
The crystallography of the intermetallic phases forming at the zinc-film/substrate interfaces in hot-dip galvanizing steel sheets has been investigated mainly by means of scanning electron and cross sectional transmission electron microscopies. Zinc atoms penetrating into a ferrite lattice precipitate within the ferrite as monoclinic ζ-phase rods with parallelogram cross sections initially in contact with the interface. The growth direction of the ζ-phase rod is probably the ζ which lies parallel to a <111>α. The orientation relationship between ζ and the substrate ferrite, ζ//α, (100)ζ//(101)α, (010)ζ//(121)α, can be expected by considering both the results of scanning microscopy and the atomic configurations of ζ phase and those of ferrite. The additional heat cycle up to 723 K to produce thin foils for cross sectional transmission electron microscopy after the hot-dip galvanizing process induces the formation of δ1-phase at the ferrite/ζ interphase boundary. No specific orientation relationship between the δ1-phase and the substrate ferrite was obtained.