Orientation domains and texture in hot-dipped galvanized coatings

Abstract

A. SÉ MOROZ, L. STREZOV, and M. RAPPAZThe crystallographic orientation of galvanized coatings (Zn-0.2Al-0.15Sb in wt pct) has been characterized by Electron-Backscattered Diffraction (EBSD) and optical microscopy. While 80 pct of the nucleation spots in the coating give rise to single-crystal Zn grains, it has been found that about 20 pct of them give rise to two or more orientation domains, each having a specific crystallographic orientation. For such "polycrystalline Zn grains," the orientations of the domains are crystallographically related: they have a dense crystallographic direction (͗1010͘, ͗1120͘, or ͗0001͘) in common. Moreover, the crystallographic relationships are similar to those observed in snowflakes and can be partially explained by the concept of a coincidence-site lattice (CSL). The EBSD measurements were also used in order to measure quantitatively the crystallographic texture. In particular, it has been evidenced that the (0001) texture of galvanized coatings is the result of two contributions: (1) the nuclei are preferentially oriented with the basal plane parallel to the coating plane (33 pct of the grains have an angle between the basal plane and the coating plane smaller than 22.5 deg), and (2) the grains having the basal plane parallel to the coating plane grow faster (these grains represent 43 pct of the coating surface). This reinforcement of the texture during growth is in agreement with that predicted by growth models, which take into account the effect of the interfaces.

Designing the Color of Hot-Dip Galvanized Steel Sheet Through Destructive Light Interference Using a Zn-Ti Liquid Metallic Bath

“…Diffusion of Ti +4 ions through the ionic lattice of TiO 2 It was proven above that the rate-limiting step of TiO 2 growth is the diffusion of Ti +4 ions through the ionic lattice of TiO 2 . Then, the thickness of the TiO 2 layer is written as [30] …”

“…[1][2][3][4][5][6][7][8][9] In addition to obvious corrosion requirements, the interest in decorative use of colored coatings has recently increased. [10][11][12] These two fields have been combined in some patents and research papers.…”

Formation of zinc interlayer texture during dissimilar ultrasonic spot welding of magnesium and high strength low alloy steel

“…Chen and Nakata [2,8] and Xu et al [9] who conducted XRD analysis at the fracture surfaces of Mg and steel side of the Mg to Zn coated steel joint for FSW and RSW respectively did not find a strong basal crystallographic texture in the Zn interlayer. Since failure occurred through the Zn interlayer and the preferential slip plane of Zn (hexagonal close-packed structure) is known to be (0 0 0 2) basal plane for plastic deformation at room temperature [17,18], texture variations could affect the tensile properties of Zn interlayer. Therefore, study of the texture on the Zn interlayer is required.…”

“…Textures in hexagonal metals have attracted significant interest over the years because of their widespread use [16]. Many studies have shown texture behavior of Zn coated steel [17,18]. However, the question remains unclear about the effect of the welding process on the texture behavior of Zn coating.…”

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

“…That is to say, when the c-axes of the zinc grains trend to be perpendicular to the direction of the tensile stress, the plastic deformation via basal slip become less and those via non-basal slip and twinning become dominate. (0 0 0 1) fiber texture in zinc coatings prepared by hot-dip galvanizing is often detected [21,22] because the growth rate along the 1 0 1 0 direction is much faster than that along 0 0 0 1 direction during the solidification process of zinc coating [22]. As the (0 0 0 1) fiber texture in the zinc coating is strong, i.e.…”