In-situ localization of damage in a Zn-Al-Mg coating deposited on steel by continuous hot-dip galvanizing

TL;DR

This paper investigates the damage mechanisms in Zn-Al-Mg coatings on steel, revealing how twinning can cause crack initiation in eutectic regions through in-situ SEM tensile testing.

Contribution

It introduces a new understanding of deformation and damage mechanisms, specifically twinning-induced crack initiation in Zn-Al-Mg coatings.

Findings

Twinning can induce crack initiation in eutectic regions.

In-situ SEM tensile testing clarifies damage progression.

Heterogeneous microstructure influences damage mechanisms.

Abstract

Zn-Al-Mg coatings are characterized by a complex microstructure with dendritic and eutectic phases. This heterogeneous phase distribution contributes to multiple deformation and damage mechanisms. The presence of brittle phases promotes crack initiation and propagation. This study reveals a new deformation and damage mechanism of a Zn-Al-Mg coating, where twinning can induce crack initiation in the eutectic region. The chronology of different events leading to crack initiation and propagation is clearly established by in-situ tensile testing in a scanning electron microscope, which helps to establish a detailed characterization of the mechanical behavior of the coating.