Microstructures and Properties of Laser Al Alloying on AZ31 Magnesium Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 867-870 ◽  
Author(s):  
Hong Ye ◽  
Xiao Bin Zhang ◽  
Xia Chang ◽  
Rui Chen
Keyword(s):  
Wear Resistance ◽  
Magnesium Alloy ◽  
Corrosion Behaviour ◽  
Thermal Spraying ◽  
Hardness Measurement ◽  
Alloy Layer ◽  
Az31 Magnesium Alloy ◽  
X Ray Diffraction ◽  
The Matrix ◽  
Al Coating

In order to improve corrosion and wear resistance of magnesium alloy, Al coating was prepared on the AZ31 magnesium alloy by the thermal spraying, then the Al-rich layer was obtained by using a CO2 laser re-melting. The microstructures and phases of the alloying layer were analyzed by canning electron microscope (SEM) and X-ray diffraction apparatus (XRD). The mechanical properties were investigated by using hardness measurement and ring-on-flat apparatus. The corrosion behaviour was investigated in 3.5% (mass fraction) NaCl solution by electrochemical measurements. The results show that there are several different microstructures in the alloying layer, such as columnar, snowflake and network structure; the alloying layer consist of Mg2Al3, Mg17Al12 and α-Mg phases. The microhardness of alloy layer is about 170HV, higher than that of the AZ31 matrix (about 50HV). The wear tests show that the wear resistance of alloying layer is considerably improved comparing with the matrix. The potentiodynamic polarization results indicate that the corrosion resistance by laser alloying is enhanced.

Room Temperature Screw Form Rolling of AZ91D Magnesium Alloy through Processing by Extrusion-Torsion Simultaneous Working

2014 ◽  
Vol 783-786 ◽  
pp. 375-379
Author(s):  
Mitsuaki Furui ◽  
Shouyou Sakashita ◽  
Kazuya Shimojima ◽  
Tetsuo Aida ◽  
Kiyoshi Terayama ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Room Temperature ◽  
Hardness Measurement ◽  
Rolling Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Az91d Magnesium Alloy ◽  
Microstructure Observation ◽  
Fine Grain ◽  
Simultaneous Processing

Extrusion-torsion simultaneous processing is a very attractive technique for fabricating a rod-shape material with fine grain and random texture. We have proposed a new screw form rolling process combined with preliminary extrusion-torsion simultaneous working. Microstructure evolution and mechanical property change of AZ91D magnesium alloy during extrusion-torsion simultaneous processing was examined through microstructure observation, X-ray diffraction analysis and micro-Vickers hardness measurement. By the addition of torsion, the crystal orientation of AZ91D magnesium alloy workpiece was drastically changed from basal crystalline orientation to the random orientation. Crystal grain occurred through the dynamic recrystallization and tended to coarsen with an increase of extrusion-torsion temperature. Grain refinement under 2 um was achieved at the lowest extrusion-torsion temperature of 523 K. M8 gauge AZ91D magnesium alloy screw was successfully formed at room temperature using the extrusion-twisted workpiece preliminary solution treating at 678 K for 345.6 ks. It was found that the extrusion-torsion temperature of 678 K must be selected to fabricate the good screw without any defects.

scholarly journals INFLUENCE OF A PREFABRICATED-CROWN ROLLING PROCESS ON THE CORROSION BEHAVIOUR OF AZ31 MAGNESIUM ALLOY

2021 ◽  
Vol 55 (4) ◽  
Author(s):  
Zhiquan Huang ◽  
Jinchao Zou ◽  
Junpeng Wang ◽  
Yanjie Pei ◽  
Renyao Huang ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Plate Thickness ◽  
Az31 Alloy ◽  
Rolling Process ◽  
Charge Transfer Resistance ◽  
Az31 Magnesium Alloy ◽  
Transfer Resistance

The present study aims to investigate the effect of a prefabricated-crown rolling process on the corrosion characteristic of the AZ31 magnesium alloy. Specimens made of the AZ31 alloy were rolled under various crown conditions, and their microstructure evolution and corrosion behavior were analyzed. The corrosion behavior was studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed that the corrosion-current density of the AZ31 alloy with a side pressure of 37.5 % of the plate thickness of the precast convexity decreased from 3.79 × 10–6 A/cm2 to 1.80 × 10–6 A/cm2, and the difference between the edge and the middle of the AZ31 alloy was shortened from 2.05 × 10–6 A/cm2 to 1.14 × 10–6 A/cm2. The charge-transfer resistance also increased from 507.1 Ω·cm2 to 581.2 Ω·cm2. The improvement in the corrosion resistance is a result of the more stable corrosion products and microstructure refinement formed after the prefabricated-crown rolling process.

Microstructure and Property of Wear-Resistant Coating Layer by High-Frequency Induction Cladding on Mild Steel Surface

2011 ◽  
Vol 239-242 ◽  
pp. 773-776
Author(s):  
Li Yang ◽  
Gang Li
Keyword(s):  
Wear Resistance ◽  
Mild Steel ◽  
High Frequency ◽  
Coating Layer ◽  
High Hardness ◽  
Alloy Coating ◽  
Alloy Layer ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Frequency Induction

In order to improve the wear resistance of mild steel products, the Fe-based alloy layer was melted on the surface of mild steel by high-frequency induction cladding. Using scanning electron microscopy, energy dispersive spectroscopy and x-ray diffraction observation of microstructure of the alloy coating, wear resistance of the coating was evaluated. The results showed that: between the coating and the substrate is metallurgical bonded; The microstructure of coating layer was compact actinomorphous structure with plentiful nubby and strip eutectics; Actinomorphous structure was mixed structure of martensite and γ alloy solid solution covered with a large number floriform and dendrite eutectic; The coating has high hardness and good wear resistance.

Comparison of Different Content of Cd and Sb Element on the Microstructure, Mechanical Properties of As-Cast AZ31 Magnesium Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 197-201
Author(s):  
Xiao Ping Luo ◽  
Lan Ting Xia ◽  
Ming Gang Zhang
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Az31 Alloy ◽  
Hexagonal Structure ◽  
Az31 Magnesium Alloy ◽  
The Matrix ◽  
The Difference ◽  
Significant Addition ◽  
Different Content ◽  
New Phase

The effect of Cd and Sb addition on the microstructural and mechanical properties of as-cast AZ31 alloys was investigated and compared. The results indicate that the difference of Sb and Cd in the microstructure and mechanical properties of as-cast AZ31 magnesium alloy is significant. Addition of 0.15%Sb (mass fraction) to AZ31 alloy can refine the matrix and β-Mg17Al12phase but not form a new phase Mg3Sb2. Oppositely, by addition of 0.3-0.7% Cd to AZ31 alloy, Cd was dissolved into the AZ31 alloy, the phase composition did not change but was refined also. Accordingly, the Cd-refined AZ31 alloy exhibits higher tensile and impact toughness and Brinell hardness properties than the Sb- refined one. The difference of Sb and Cd in the mechanical properties is possibly related to the solid solution of Cd into the matrix and formation of Mg3Sb2which has the same close-packed hexagonal structure as α-Mg.

scholarly journals Corrosion behaviour of AZ31 magnesium alloy with different grain sizes in simulated biological fluids☆

2010 ◽  
Vol 6 (5) ◽  
pp. 1763-1771 ◽  
Author(s):  
M. Alvarez-Lopez ◽  
María Dolores Pereda ◽  
J.A. del Valle ◽  
M. Fernandez-Lorenzo ◽  
M.C. Garcia-Alonso ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Behaviour ◽  
Biological Fluids ◽  
Az31 Magnesium Alloy ◽  
Grain Sizes

Investigation of High Performance Diamond Brazed Saw for Cutting AZ31 Magnesium Alloy

2011 ◽  
Vol 487 ◽  
pp. 347-351
Author(s):  
Bo Jiang Ma ◽  
X. Cai ◽  
L.A. Li
Keyword(s):  
Magnesium Alloy ◽  
High Performance ◽  
Az31 Magnesium Alloy ◽  
X Ray Diffraction ◽  
Nicr Alloy ◽  
Alloy Plate ◽  
Energy Dispersion Spectrometer ◽  
Long Time ◽  
Diamond Saw ◽  
High Frequency Induction

The high performance diamond brazed saw was developed to cut efficiently AZ31 Magnesium Alloy. The Ti-coated diamond and the uncoated diamond were brazed with NiCr alloy by high-frequency induction under argon atmosphere at 1040°C within 20 seconds. Scanning electron microscopy (SEM), energy dispersion spectrometer (EDS) and X-ray diffraction (XRD) were used to investigate the interfacial microstructures between brazed diamond and the filler alloy. The results show that Cr-carbides forms normally and compactly on the surface of Ti-coated diamond brazed, whereas Cr-carbide forms tangentially and loosely on the surface of uncoated diamond brazed. That is because Ti has changed the mechanism of Cr-carbides formed on the surface of diamond brazed. The test of cutting AZ31 magnesium alloy plate shows that the section cut by Ti-coated diamond saw is much smoother than that cut by uncoated diamond saw after a long time.

scholarly journals Corrosion Behaviour of Preserved PEO Coating on AZ31 Magnesium Alloy

2020 ◽  
Vol 23 (2) ◽  
pp. B76-B88
Author(s):  
Filip Pastorek ◽  
Milan Štrbák ◽  
Daniel Kajánek ◽  
Martina Jacková ◽  
Jana Pastorková ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Treatment Process ◽  
Corrosion Behaviour ◽  
Salt Spray ◽  
Az31 Magnesium Alloy ◽  
Electrochemical Tests ◽  
Marine Transport ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

A surface treatment process, composed of plasma electrolytic oxidation (PEO) and sealing by temporary oil preservation system containing corrosion inhibitors, was performed on AZ31 magnesium alloy in order to improve its corrosion resistance in environments containing chlorides. Both atmospheric and immersion conditions were evaluated by electrochemical tests in 0.1M NaCl solution together with salt spray test according to STN EN ISO 9227 standard. The obtained results confirmed significant improvement of corrosion resistance reached by the PEO sealing in aggressive environments compared to the pure PEO coating on AZ31 surface. Hence, such a duplex coating is a very perspective alternative for magnesium alloy applications in severe conditions or for temporary protection of magnesium products coated by the PEO during marine transport.

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