scholarly journals Mechanical properties and corrosion resistance of Mg-RE cast alloys and their plasma electrolytic oxidation

2021 ◽  
Vol 2144 (1) ◽  
pp. 012010
Author(s):  
S V Zasypkin ◽  
A O Cheretaeva ◽  
M R Shafeev ◽  
D L Merson ◽  
M M Krishtal

Abstract The effect of heat treatment on the mechanical properties (hardness, plasticity, yield and tensile strength) and corrosion resistance of several cast magnesium alloys with additions of rare earth metals (Y, Nd and Gd), and their surface modification by plasma electrolytic oxidation (PEO) were investigated. It was found that the heat treatment of the alloys results information of Mg12YZn, Mg3Zn3Y2 and Mg24Y5 based LPSO-phases and causes an increase in hardness and tensile strength by 5-7 and 20-25%, respectively, but at the same time, corrosion resistance of the alloysdrops by 10-20 times. PEO of the alloys after heat treatment reduced the corrosion currents by 1-3 orders of magnitude without changing the corrosion potential.

Author(s):  
N Sivashanmugam ◽  
KL Harikrishna ◽  
S R Koteswara Rao ◽  
N Rameshbabu ◽  
P Manojkumar

Abstract Magnesium and its alloys are extensively used in the defence, aerospace and automotive industries, owing to their excellent mechanical properties. But there is a requirement of corrosion prevention treatment before using it for applications, since the corrosion resistance of Mg alloy is poor. In this work, a study on the mechanical properties of friction stir welded ZE41 rare earth magnesium alloy thick plates of 15mm and 25mm, was carried out. A metallographic examination and mechanical tests were conducted on both the welds. Furthermore, Plasma Electrolytic Oxidation (PEO), a surface conversion treatment was carried out on both the base material as well as on the friction stir butt joints. X-ray diffraction and scanning electron microscopy analysis were carried out on all the samples, with and without coating. The coated and uncoated samples were assessed by potentiodynamic polarisation (PDP) tests and electrochemical impedance spectroscopy (EIS) to study the electrochemical corrosion behaviour. An outer porous layer and an inner dense layer, have been identified from the SEM images. From the corrosion tests results it was revealed that there was an improvement in the corrosion resistance of both the base metal as well as the weldments by the PEO coating process.


2015 ◽  
Vol 53 (8) ◽  
pp. 535-540 ◽  
Author(s):  
Young Gun Ko ◽  
Dong Hyuk Shin ◽  
Hae Woong Yang ◽  
Yeon Sung Kim ◽  
Joo Hyun Park ◽  
...  

Coatings ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 4
Author(s):  
Dmitry V. Dzhurinskiy ◽  
Stanislav S. Dautov ◽  
Petr G. Shornikov ◽  
Iskander Sh. Akhatov

In the present investigation, the plasma electrolytic oxidation (PEO) process was employed to form aluminum oxide coating layers to enhance corrosion resistance properties of high-strength aluminum alloys. The formed protective coating layers were examined by means of scanning electron microscopy (SEM) and characterized by several electrochemical techniques, including open circuit potential (OCP), linear potentiodynamic polarization (LP) and electrochemical impedance spectroscopy (EIS). The results were reported in comparison with the bare 6061-O aluminum alloy to determine the corrosion performance of the coated 6061-O alloy. The PEO-treated aluminum alloy showed substantially higher corrosion resistance in comparison with the untreated substrate material. A relationship was found between the coating formation stage, process parameters and the thickness of the oxide-formed layers, which has a measurable influence on enhancing corrosion resistance properties. This study demonstrates promising results of utilizing PEO process to enhance corrosion resistance properties of high-strength aluminum alloys and could be recommended as a method used in industrial applications.


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