Microstructural basis for improved corrosion resistance of laser surface processed AZ31 Mg alloy

Saumyadeep Jana; Matt Olszta; Danny Edwards; Mark Engelhard; Avik Samanta; Hongtao Ding; Pratik Murkute; O. Burkan Isgor; Aashish Rohatgi

doi:10.1016/j.corsci.2021.109707

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Microstructural basis for improved corrosion resistance of laser surface processed AZ31 Mg alloy

Journal article

Open access

Peer reviewed

Microstructural basis for improved corrosion resistance of laser surface processed AZ31 Mg alloy

Saumyadeep Jana, Matt Olszta, Danny Edwards, Mark Engelhard, Avik Samanta, Hongtao Ding, Pratik Murkute, O. Burkan Isgor and Aashish Rohatgi

Corrosion science, Vol.191(C), p.109707

10/2021

DOI: 10.1016/j.corsci.2021.109707

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Abstract

•Mg alloy (AZ31) shows better corrosion resistance after laser surface processing.•Laser surface processing changes mode of corrosion from localized to uniform.•Laser surface processing creates ∼0.5 μm thick mixed-metal oxide surface film.•Mixed-metal oxide surface film converts to layered double hydroxide film later. Despite their excellent strength-to-weight ratio, wider use of magnesium (Mg) alloys for light-weight applications is limited by their poor corrosion resistance, especially in chloride-containing environments. The present study shows improved corrosion resistance imparted by laser surface processing (LSP) of a commercial AZ31 (Mg-3Al-1Zn) alloy. Nanosecond laser processing at three different power settings was carried out on the surface of a 1-mm-thick rolled AZ31 sheet. Electrochemical studies and salt spray testing (ASTM B117) indicate substantial enhancement of corrosion resistance in LSP-treated AZ31. The underlying reasons behind improved corrosion resistance of the LSP-AZ31 surface have been studied through detailed microstructural characterization and chemical analysis by SEM, TEM, and XPS. Formation of a ∼0.5 μm thick mixed metal (Mg, Al) oxide surface film, together with refinement in the size and number density of Al-Mn intermetallic particles, are shown to play a major role toward improved corrosion resistance after LSP treatment of the AZ31 alloy.

EIS

Localized corrosion

Magnesium

SEM

STEM

XPS

Details

Title: Subtitle: Microstructural basis for improved corrosion resistance of laser surface processed AZ31 Mg alloy
Creators: Saumyadeep Jana - Pacific Northwest National Laboratory
Matt Olszta - Pacific Northwest National Laboratory
Danny Edwards - Pacific Northwest National Laboratory
Mark Engelhard - Pacific Northwest National Laboratory
Avik Samanta - University of Iowa
Hongtao Ding - University of Iowa
Pratik Murkute - Oregon State University
O. Burkan Isgor - Oregon State University
Aashish Rohatgi - Pacific Northwest National Laboratory
Resource Type: Journal article
Publication Details: Corrosion science, Vol.191(C), p.109707
DOI: 10.1016/j.corsci.2021.109707
ISSN: 0010-938X
eISSN: 1879-0496
Publisher: Elsevier Ltd
Grant note: DOI: 10.13039/100009612, name: Oregon State University; DOI: 10.13039/100000993, name: Battelle; DOI: 10.13039/100011661, name: Pacific Northwest National Laboratory; DOI: 10.13039/100006134, name: Office of Energy Efficiency and Renewable Energy; DOI: 10.13039/100000015, name: U.S. Department of Energy, award: DE-AC05-76RL01830; DOI: 10.13039/100006206, name: Biological and Environmental Research
Language: English
Date published: 10/2021
Academic Unit: Iowa Technology Institute; Mechanical Engineering
Record Identifier: 9984196535902771

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