Compression deformability of Γ and ζ Fe–Zn intermetallics to mitigate detachment of brittle intermetallic coating of galvannealed steels

摘要

Micropillar compression tests on each of the five intermetallic phases of the Fe–Zn system, which constitute the coating of galvannealed steels, have revealed that the Γ phase formed in direct contact with the steel substrate and the ζ phase formed on the outermost surface are ductile, sandwiching the other three brittle phases (Γ1, δ1k and δ1p). Compression deformability of these ductile phases is considered to mitigate the coating failure through sustaining ruptured fragments of the brittle phases during the forming process.