Plastic Deformation and Fracture Behavior of Galvannealed Coating.

Abstract

Deformation and fracture in galvannealed coating which was subjected to tensile or compressive stress by three point bend test were investigated by scanning electron microscopy. In the coating subjected to compressive stress, cracks were generated in the d 1 phase and propagated at an angle inclined to coating plane in the d 1 phase. Then, fracture occurred within d 1 phase, or, along the G-Fe interface. In the coating subjected to tensile stress, cracks were generated in the d 1 phase and propagated perpendicularly to coating plane in the d 1 phase. Then, cracks reached and propagated along the G-Fe interface. The coating did not show any plastic deformation under tensile stress but showed apparent plastic deformation under compressive stress. During deformation of the coating and the steel substrate, there was substantial interaction and inhomogeneity. Major deformation mode in the coating was cracking while that in the steel substrate was inhomogeneous plastic deformation in the regions adjoining to the cracks, irrespective of compressive or tensile stress.

Structural and Textural Characterization of the Substrate and Coated Layer in an Industrial Galvannealed Interstitial-Free Steel

“…[4][5][6] Several efforts have been made to correlate the microstructure of galvannealed coatings to their performance, especially the coating formability during press forming operations. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] Most of the work has been carried out using galvanizing and galvannealing simulators, where the growth of the coating takes place under fully controlled experimental conditions. The relevance of the results of such investigations to the industrial galvanizing and galvannealing processes, where there is practically very little control of the working parameters during operation, is questionable.…”

Characterization of the failure behavior of zinc coating on dual phase steel under tensile deformation

“…[5][6][7][8]. Extensive researches have been done on the failure behavior of zinc coatings on steels, and the mechanisms of cracking and decohesion of coatings have been presented in detail [3][4][5][6][7][8][9][10][11][12]. Failure behavior of the zinc coatings is mainly governed by its intrinsic microstructure and the adhesion of the coating to the steel substrate.…”

Effect of Microstructure at Coating Layer on Fatigue Strength in Hot-Dip Galvanized Steel

“…However, to have a clear understanding of corrosion fatigue, it is necessary to understand, independently, the behavior of corrosion and fatigue, respectively. To date, a substantial amount of research has been carried out on corrosion of galvanized steel, [1][2][3] forming of alloy layer [4][5][6] and peeling of plating film, 7,8) to ensure high reliability. On the other hand, studies on the fatigue strength of hot-dip galvanized steels focus mainly on specific areas such as…”