scholarly journals Microstructure and Corrosion Behavior of Extruded Mg-Sn-Y Alloys

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1095
Author(s):  
Devadas Bhat Panemangalore ◽  
Rajashekhara Shabadi ◽  
Manoj Gupta ◽  
Ludovic Lesven
Keyword(s):  
Corrosion Resistance ◽  
Elemental Composition ◽  
Oxide Layer ◽  
Corrosion Behavior ◽  
Potentiodynamic Polarization ◽  
Density Ratio ◽  
High Strength ◽  
Pure Magnesium ◽  
Alloying Elements ◽  
Present Effort

Magnesium and its alloys, with their unique properties such as high strength/density ratio, good castability, and machinability, have found several applications in the aerospace and automotive industries. One of the reasons that restrict their widespread applicability is their poor corrosion resistance since Mg is readily oxidized in the presence of oxygen and humidity. The oxide layer is pseudo-passive and non-protective. The present effort tried to improve the passivity of this layer with the addition of alloying elements such as Tin (Sn) and Yttrium (Y) to create phases that interact differently with the oxidizing environment, thereby improving the corrosion resistance. In this work, the corrosion behavior of pure magnesium and Mg-5Sn-xY (x = 0.5, 1, 2 wt.%) were evaluated using immersion and potentiodynamic polarization tests. XRD, SEM-EDS, and EBSD have investigated the microstructure and elemental composition of the alloys. The present study is focused on elucidating the microstructure-corrosion relationship in Mg-Sn-Y alloys.

Corrosion Mechanisms of New Wrought Mg-Al Based Alloys Alloying with Mn, Zn and Sn

2018 ◽  
Vol 941 ◽  
pp. 1880-1885
Author(s):  
Guy Ben Hamu ◽  
Polina Metalnikov ◽  
Dan Eliezer ◽  
Kwang Seon Shin
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Weight Ratio ◽  
High Strength ◽  
Immersion Test ◽  
Alloying Elements ◽  
Corrosion Propagation ◽  
Corrosion Mechanisms ◽  
Mechanical Properties And Corrosion

The low density and high strength/weight ratio of magnesium (Mg) and magnesium alloys make them promising candidate materials in light-weight vehicle industries, such as automobile and aerospace, where poor corrosion resistance is a major obstacle in many of their wide-spread applications. Addition of alloying elements with production of wrought Mg alloys with finer microstructure results in enhanced mechanical properties and corrosion resistance. The aim of this research is to study the changes in microstructure caused by addition of alloying elements (zinc (Zn), and tin (Sn)) to new wrought Mg-5Al alloy, and their influence on the alloy's corrosion behavior. The microstructure was investigated using optical and electron microscopy and EDS. The corrosion behavior was analyzed through electrochemical measurements and immersion test. It was found that the corrosion resistance of Mg-5Al alloy was improved by addition of alloying elements, and the amounts of these elements strongly influenced the corrosion behavior of the alloys. Nevertheless, the influence of alloying elements is different for short-term and long-term immersion periods, since the mechanisms of corrosion initiation and corrosion propagation are different.

Development of New Wrought Mg Alloys: Improving the Corrosion Resistance by Addition of Alloying Elements

2020 ◽  
Vol 27 ◽  
pp. 50-60
Author(s):  
Guy Ben Hamu ◽  
Polina Metalnikov
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Oxide Layer ◽  
Weight Ratio ◽  
High Strength ◽  
Mg Alloys ◽  
Alloying Elements ◽  
Second Phase ◽  
Second Phase Particles ◽  
Superior Corrosion Resistance

Magnesium (Mg) alloys constitute an attractive structural material for transportation industries, due to their low density and high strength/weight ratio. However, high susceptibility to corrosion of Mg alloys limits their use. Therefore, there is a growing interest for development of new Mg alloys with good mechanical properties and superior corrosion resistance. Production of wrought Mg alloys results in enhancement of mechanical properties, whereas addition of alloying elements may result in improved corrosion behavior. In this study we distinguish the role of aluminum, zinc, tin and calcium additions on the corrosion performance of new wrought Mg alloys. Overall, addition of alloying elements resulted in precipitation of second phase particles with cathodic behavior (relatively to Mg matrix). This enhanced the micro-galvanic effects and the corrosion resistance in short periods of immersion was deteriorated. However, in longer periods of immersion the passive characteristics of the oxide layer played a significant role in improving the alloys' corrosion resistance. The contribution of each element to the oxide layer will be discussed in detail. In general, the quantities of alloying element should be sufficient to stabilize the corrosion products layer; yet as low as possible, in order to reduce the micro-galvanic effects.

Analysis on Finish Hard Turning of Ti-6.5Al-3.5Mo-1.5Zr-0.3Si Alloy

2009 ◽  
Vol 626-627 ◽  
pp. 225-230 ◽  
Author(s):  
Wei Wei Ming ◽  
Ming Chen ◽  
Bin Rong
Keyword(s):  
Corrosion Resistance ◽  
Elevated Temperature ◽  
Tool Wear ◽  
Hard Turning ◽  
Density Ratio ◽  
High Strength ◽  
Excellent Performance ◽  
Good Corrosion Resistance ◽  
Tool Wear Mechanism ◽  
Finish Hard Turning

Titanium alloys are extensively applied in aerospace, automotive, biomedical, and chemical industries owing to their excellent performance combining high strength-to-density ratio, good corrosion resistance, and high strength at elevated temperature. Ti-6.5Al-3.5Mo-1.5Zr-0.3Si (TC11) alloys are used to replace the most common Ti-6Al-4V in some important applications such as some parts in aerospace engine. The purpose of this paper is to evaluate the machinability of TC11 alloys in the finish hard turning conditions. The paper presents the machinability results of TC11 alloys compared with Ti-6Al-4V, and analyzes the variables such as cutting force, surface integrity, and tool wear mechanism in the experiments.

scholarly journals Electrochemical Anodizing Treatment to Enhance Localized Corrosion Resistance of Pure Titanium

2017 ◽  
Vol 15 (1) ◽  
pp. 19-24 ◽  
Author(s):  
Davide Prando ◽  
Andrea Brenna ◽  
Fabio M. Bolzoni ◽  
Maria V. Diamanti ◽  
Mariapia Pedeferri ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Titanium Alloys ◽  
Oxide Layer ◽  
Corrosion Behavior ◽  
Pure Titanium ◽  
Localized Corrosion ◽  
Anodic Current Density ◽  
Anodic Current ◽  
Protective Oxide ◽  
Pitting Potential

Background Titanium has outstanding corrosion resistance due to the thin protective oxide layer that is formed on its surface. Nevertheless, in harsh and severe environments, pure titanium may suffer localized corrosion. In those conditions, costly titanium alloys containing palladium, nickel and molybdenum are used. This purpose investigated how it is possible to control corrosion, at lower cost, by electrochemical surface treatment on pure titanium, increasing the thickness of the natural oxide layer. Methods Anodic oxidation was performed on titanium by immersion in H2SO4 solution and applying voltages ranging from 10 to 80 V. Different anodic current densities were considered. Potentiodynamic tests in chloride- and fluoride-containing solutions were carried out on anodized titanium to determine the pitting potential. Results All tested anodizing treatments increased corrosion resistance of pure titanium, but never reached the performance of titanium alloys. The best corrosion behavior was obtained on titanium anodized at voltages lower than 40 V at 20 mA/cm2. Conclusions Titanium samples anodized at low cell voltage were seen to give high corrosion resistance in chloride- and fluoride-containing solutions. Electrolyte bath and anodic current density have little effect on the corrosion behavior.

scholarly journals Erosion-Corrosion Protection Due to Cr3C2-NiCr Cermet Coating on Stainless Steel

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1042
Author(s):  
Panneer Selvam Kevin ◽  
Abhishek Tiwari ◽  
Saravanan Seman ◽  
Syed Ali Beer Mohamed ◽  
Rengaswamy Jayaganthan
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Potentiodynamic Polarization ◽  
Electrochemical Impedance ◽  
Turbine Blades ◽  
Continuous Exposure ◽  
Hydro Power ◽  
Cermet Coating ◽  
Erosion Corrosion

Cr3C2–NiCr coatings have been used extensively to combat the erosion corrosion of hydro power turbine blades made of stainless steel. Cr3C2–NiCr coatings are also used in aqueous corrosive environments due to the high corrosion resistance rendered by the NiCr binder. In this investigation, both erosion and corrosion environments are introduced to cermet coating to study corrosion behavior using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The cermet coatings are useful for reducing the risk of deterioration of mechanical properties of hydro power turbines due to the continuous exposure to the erosive and corrosive action of the corrosive environment containing silt. It was observed that Cr3C2–NiCr coating offered a reasonable improvement in corrosion resistance when compared to bare substrate. The corrosion behavior of the coating was studied in a 150 mL solution of 0.1 M NaCl with 2 gms of quartz particles (0.2–0.8 mm) at various rotation speeds (3000, 4500, 6000 rpm) of the solution over a 1 h immersion using potentiodynamic polarization and EIS studies in a specifically designed experimental set-up for erosion corrosion. When compared to the bare stainless steel samples at 3000 rpm and 6000 rpm, the coating showed the highest improvement at 6.57 times and the least improvement at 3.79 times, respectively.

EFFECT OF FRICTION STIR PROCESSING ON CORROSION BEHAVIOR OF CAST AZ91C MAGNESIUM ALLOY

2019 ◽  
Vol 26 (06) ◽  
pp. 1850213 ◽  
Author(s):  
BEHZAD HASSANI ◽  
RUDOLF VALLANT ◽  
FATHALLAH KARIMZADEH ◽  
MOHAMMAD HOSSEIN ENAYATI ◽  
SOHEIL SABOONI ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Corrosion Behavior ◽  
Friction Stir Processing ◽  
Potentiodynamic Polarization ◽  
Passive Layer ◽  
Friction Stir ◽  
T6 Heat Treatment ◽  
Az91c Magnesium Alloy

The corrosion behavior of as-cast AZ91C magnesium alloy was studied by performing friction stir processing (FSP) and FSP followed by solution annealing and then aging. Phase analysis, microstructural characterization, potentiodynamic polarization test and immersion tests were carried out to relate the corrosion behavior to the samples microstructure. The microstructural observations revealed the breakage and dissolution of coarse dendritic microstructure as well as the coarse secondary [Formula: see text]-Mg[Formula: see text]Al[Formula: see text] phase which resulted in a homogenized and fine grained microstructure (15[Formula: see text][Formula: see text]m). T6 heat treatment resulted in an excessive growth and dispersion of the secondary phases in the microstructure of FSP zone. The potentiodynamic polarization and immersion tests proved a significant effect of both FSP and FSP followed by T6 on increasing the corrosion resistance of the cast AZ91C magnesium alloy. Improve in corrosion resistance after FSP was attributed to grain refinement and elimination of segregations and casting defects which makes more adhesive passive layer. Increase in volume fraction of precipitations after T6 heat treatment is determined to be the main factor which stabilizes the passive layer at different polarization values and is considered to be responsible for increasing the corrosion resistance.

scholarly journals Investigation of Microstructure, Nanohardness and Corrosion Resistance for Oxi-Nitrocarburized Low Carbon Steel

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 190 ◽  
Author(s):  
Young-Wook Cho ◽  
Young-Joon Kang ◽  
Ju-Hwan Baek ◽  
Jeong-Ho Woo ◽  
Young-Rae Cho
Keyword(s):  
Corrosion Resistance ◽  
Carbon Steel ◽  
Oxide Layer ◽  
Potentiodynamic Polarization ◽  
Low Carbon Steel ◽  
Nanoindentation Test ◽  
Low Carbon ◽  
Electron Backscattered Diffraction ◽  
Corrosion Properties ◽  
Process Gas

A role of oxi-nitrocarburizing technique for low-carbon steel was intensively evaluated as a means of reducing the problem of corrosion in gas nitrocarburizing, which is a vital disadvantage of gas nitrocarburizing. Oxi-nitrocarburizing was carried out by a two-step process: Gas nitrocarburizing at 560 °C and oxidation. In order to characterize two different methods of oxi-nitrocarburizing, oxidation was performed under two different conditions: Air and steam as oxygen sources. To analyze the microstructural, physical, and chemical properties of the thin oxide layer and nitride layer, which are the surface hardened layers formed on low-carbon steel by oxi-nitrocarburizing, several methods, such as electron probe microanalysis (EPMA), electron backscattered diffraction (EBSD), scanning electron microscopy (SEM), nanoindentation tests, and potentiodynamic polarization tests were applied. The results indicated that the EPMA and EBSD methods are powerful techniques for the analysis of microstructure, such as phase analysis and metallic element distribution in the oxide layer of magnetite and compound layer of ε-phase and γ'-phase, for oxi-nitrocarburized low-carbon steel. Additionally, the nanohardness using the nanoindentation test and corrosion resistance using the potentiodynamic polarization test for the oxi-nitrocarburized specimens are useful methods to understand the mechanical and corrosion properties of the surface hardened layer.

Correlation of Surface Alloyed Microstructure of Pure Magnesium With its Corrosion Behavior

2012 ◽  
Vol 472-475 ◽  
pp. 161-164
Author(s):  
Yu Gao Liu
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Chloride Solution ◽  
Diffusion Time ◽  
Point Of View ◽  
Pure Magnesium ◽  
Corrosion Mechanism ◽  
Cross Sectional ◽  
Microstructure Characteristics ◽  
Solid Diffusion

This paper represents a summary of experimental results dealing with the time dependence of surface diffusion alloyed microstructure and its corrosion behavior at given temperature. The experiments were performed at 485°C for different solid diffusion time (6h, 12h, 18h ) and thus the surface alloyed microstructure of pure magnesium has been obtained. Optical and electrical microscopy and EDS compositions analysis were used to examine the cross sectional microstructure characteristics of alloyed layers of treated samples. It is shown that the new phases formed and its continuity, depending on the diffusion treated time at given temperature, have a noticeable influence on corrosion resistance and corrosion mechanism. The new formed phase Al5Mg11Zn4 was inert to the chloride solution compared with pure magnesium and acted as a corrosion barrier. It was concluded that the continuous Al5Mg11Zn4 phase was beneficial from the point of view of corrosion resistance.

Effect of high temperature compression deformation strain rate on the microstructure and corrosion behavior of 2205 duplex stainless steel

2015 ◽  
Vol 62 (3) ◽  
pp. 163-171 ◽  
Author(s):  
Yinhui Yang ◽  
Biao Yan
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Strain Rate ◽  
Duplex Stainless Steel ◽  
Corrosion Behavior ◽  
Potentiodynamic Polarization ◽  
Phase Interface ◽  
Content Type ◽  
2205 Duplex Stainless Steel

Purpose – The aim of this paper was to investigate the effect of strain rate on microstructure and corrosion behavior of 2205 duplex stainless steel, after high-temperature compression tests. Design/methodology/approach – The specimens were prepared using a Gleeble3800 thermo-simulation machine over a range of temperatures from 850 to 1,250°C and strain rates from 0.005 to 5 s−1, and the corresponding flow curves and deformation microstructure obtained were further analyzed. To evaluate the effect of strain rate on corrosion behavior, potentiodynamic polarization tests and double-loop electrochemical potentiodynamic reactivation (DL-EPR) were used to characterize the electrochemical performance. Findings – Compared with strain rate of 0.5 s−1, the worst corrosion resistance behavior from the potentiodynamic polarization test results after deformation at 0.005 s−1 was attributed to more austenite (γ) and ferrite (δ) grain boundaries or δ/γ phase interface formation due to the better effect of γ dynamic recrystallization (DRX) or δ dynamic recovery (DRV). Increasing strain rate to 5 s−1 lowered the corrosion resistance, due to the increase in dislocation density. At the low strain rate of 0.005 s−1, the susceptibility to intergranular corrosion (IGC) was comparatively high after deformation at 1050 and 1150°C with more γ/γ grains and δ/γ phase boundary formation, which was lowered with the strain rate increase to 0.5 s−1, due to suppressing effect of γ DRX. Originality/value – The paper provides the scientific basis for the practical application of hot working of 2205 duplex stainless steel.

Electrochemical corrosion behavior and surface passivation of bulk nanocrystalline copper in alkaline solution

2020 ◽  
Vol 67 (5) ◽  
pp. 465-472
Author(s):  
Wei Luo ◽  
Lei Hu ◽  
Yimin Xv ◽  
Jian Zhou ◽  
Wentao Xv ◽  
...  
Keyword(s):  
Grain Size ◽  
Corrosion Resistance ◽  
Passive Film ◽  
Corrosion Behavior ◽  
Potentiodynamic Polarization ◽  
Electrochemical Corrosion ◽  
Content Type ◽  
Naoh Solution ◽  
Electrochemical Corrosion Behavior ◽  
Bulk Nanocrystalline

Purpose This paper aims to focus on an assessment of the electrochemical corrosion performance of bulk NC copper in a variety of corrosion environments. Design/methodology/approach The electrochemical corrosion behavior of bulk nanocrystalline (NC) copper prepared by inert gas condensation and in situ warm compress technique was studied by using potentiodynamic polarization and electrochemical impedance spectroscopy tests in de-aerated 0.1 M NaOH solution. Findings NC copper exhibited a typical active-passive-transpassive behavior with the formation of duplex passive films, which was qualitatively similar to coarse-grain (CG) copper. Although a compact passive film formed on NC copper surface, the corrosion resistance of NC copper was lower in comparison with CG copper. The increase in corrosion rate for NC copper was mainly attributed to the high activity of surface atoms and intergranular atoms. These atoms led to an enhancement of passive ability and an increase of dissolution rate of passive film in oxygen-deficiency solution. For NC copper, the corrosion resistance decreased as grain size increased in NC range. Originality/value The difference in corrosion resistance between bulk NC copper and its CG counterpart is dependent upon the corrosion solution. In a previous work, the potentiodynamic polarization tests revealed that NC copper bulks (grain size 48, 68, 92 nm) had identical corrosion resistance to CG copper bulk in naturally aerated 0.1 M NaOH solution. The results might be related to the dissolved oxygen in the medium.

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