Effect of hot extrusion on AZ91 alloy corrosion behaviour

2021 ◽  
pp. 1-7
Author(s):  
Xiao-yu Fu ◽  
Rui-ling Jia ◽  
Yan-fang Ding ◽  
Tian-hao Gong ◽  
Wen Ma ◽  
...  
Keyword(s):  
Corrosion Behaviour ◽  
Hot Extrusion ◽  
Az91 Alloy

Application of Electron Microscopy to Investigation of Corrosion of Mg-Al Alloys in Various Electrolyte Solutions

2015 ◽  
Vol 231 ◽  
pp. 41-47
Author(s):  
Bartosz Chmiela ◽  
Adrian Mościcki ◽  
Maria Sozańska
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Pressure ◽  
Corrosion Behaviour ◽  
Intermetallic Phase ◽  
Electrolyte Solutions ◽  
Magnesium Hydride ◽  
Al Alloys ◽  
Az91 Alloy ◽  
Nacl Solution ◽  
Hydrogen Trap

The Mg-Al alloys are the best-known and most commonly used magnesium alloys (especially AZ91 alloy). However, the AZ91 alloy offers insufficient corrosion resistance. Many investigations show that hydrogen is the main corrosive factor appearing during chemical reactions between magnesium and water in electrolyte solution. The main intermetallic phase in the AZ91alloy is the Mg17Al12 (β phase), which is a hydrogen trap. During corrosion, magnesium hydride forms inside the β phase, and this phase is brittle fractured when the inner stress caused by hydrogen pressure and expansion stress due to the formation of magnesium hydride is higher thanthe fracture strength. We examined the corrosion behaviour of AZ91 and AE44 magnesium alloysin 0.1M Na2SO4 solution and 3.5% NaCl solution. We analysed two Mg-Al alloys in order todetermine the various effects of hydrogen on these materials.

scholarly journals Corrosion Behaviour of Mg98.5Nd1Zn0.5 (at. %) Alloy in Phosphate Buffered Saline Solution

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 148
Author(s):  
Sandra Cabeza ◽  
Pablo Pérez Zubiaur ◽  
Gerardo Garcés ◽  
Carmen Andrade ◽  
Paloma Adeva
Keyword(s):  
Corrosion Rate ◽  
Volume Fraction ◽  
Corrosion Behaviour ◽  
Hot Extrusion ◽  
High Volume ◽  
Hydrogen Release ◽  
Potential Candidate ◽  
Electrochemical Testing ◽  
Average Grain Size ◽  
Phosphate Buffered Saline

The corrosion behaviour of Mg98.5-Nd1-Zn0.5 (at. %) alloy was studied in phosphate buffered saline (PBS) solution to evaluate its degradation performance as a potential candidate for biomedical applications. The alloy, produced by casting and hot extrusion, consists of a fine-grained magnesium matrix with an average grain size of 3.8 μm embedding a high volume fraction of (Mg, Zn)12Nd precipitates. Hydrogen release tests revealed a stable low corrosion rate of 0.6 mm/year after 24 h of immersion. Electrochemical testing data proved good correlation with the data from hydrogen evolution, with the corrosion rate stabilizing below 1 mm/year.

Microstructure evolution of AZ91 alloy during hot extrusion process with various ram velocity

Vacuum ◽  
2018 ◽  
Vol 150 ◽  
pp. 136-143 ◽  
Author(s):  
Liang Chen ◽  
Mengchao Liang ◽  
Guoqun Zhao ◽  
Jixue Zhou ◽  
Cunsheng Zhang
Keyword(s):  
Microstructure Evolution ◽  
Hot Extrusion ◽  
Extrusion Process ◽  
Az91 Alloy

High-Strength AZ91 Alloy Fabricated by Rapidly Solidified Flaky Powder Metallurgy and Hot Extrusion

2018 ◽  
Vol 25 (2) ◽  
pp. 372-380 ◽  
Author(s):  
Taekyung Lee ◽  
Michiaki Yamasaki ◽  
Yoshihito Kawamura ◽  
Jongbin Go ◽  
Sung Hyuk Park
Keyword(s):  
Powder Metallurgy ◽  
Hot Extrusion ◽  
High Strength ◽  
Az91 Alloy ◽  
Rapidly Solidified

scholarly journals Fabrication of Carbon Nanotubes and Rare Earth Pr Reinforced AZ91 Composites by Powder Metallurgy

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Ning Li ◽  
Hong Yan ◽  
Qingjie Wu ◽  
Zeyu Cao
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Powder Metallurgy ◽  
Extrusion Direction ◽  
Milled Powder ◽  
Hot Extrusion ◽  
Interfacial Bonding ◽  
Tensile Fracture ◽  
Az91 Alloy ◽  
The Matrix

AbstractIt can be known from a large number of research results that improving the dispersibility of CNTs can effectively optimize the mechanical properties of the corresponding metal matrix composites. However, the crucial issue of increasing the bonding of CNTs and the matrix is still unsolved. In this paper, a novel method was developed to increase interfacial bonding strength by coating titanium oxide (TiO2) on the surface of CNTs. The rare earth Pr and TiO2@CNTs-reinforced AZ91matrix composites were successfully fabricated by powder metallurgy. Hot press sintering and hot extrusion of the milled powder was performed. After hot extrusion, the influence of TiO2@CNTs on the microstructure and mechanical properties of the composites were investigated. The results showed that the coating process can improve the distribution of CNTs in Mg alloy. The CNTs refined the grains of the matrix, and the CNTs were presented throughout the extrusion direction. When the TiO2@CNTs content was 1.0 wt.%, the yield strength (YS), ultimate tensile strength (UTS), and elongation of the alloy attained maximum values. The values were improved by 23.5%, 82.1%, and 40.0%, respectively, when compared with the AZ91 alloy. Good interfacial bonding was achieved, which resulted in an effective tensile loading transfer at the interface. CNTs carried the tensile stress and were observed on the tensile fracture.

scholarly journals A Novel Turning-Induced-Deformation Based Technique to Process Magnesium Alloys

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 841 ◽  
Author(s):  
Sravya Tekumalla ◽  
Manasa Ajjarapu ◽  
Manoj Gupta
Keyword(s):  
Mechanical Properties ◽  
Energy Efficiency ◽  
Magnesium Alloy ◽  
Plastic Strain ◽  
Magnesium Alloys ◽  
Hot Extrusion ◽  
Az91 Alloy ◽  
Depth Of Cut ◽  
Turning Process ◽  
Fine Grained

A magnesium alloy was fabricated through the consolidation of chips accumulated during the turning process, followed by cold compaction and hot extrusion. A variation in the depths of cut was done during turning to understand the effect of deformation imparted during primary processing on the mechanical properties of an AZ91 alloy (Mg–9 wt.% Al–1 wt.% Zn–0.3 wt.% Mn). The results revealed a significant improvement in compressive strengths (up to 75%) with increased depth of cut, without compromising ductility through the development of fine-grained structures and prior plastic strain induction. This approach resulted in superior materials vis-a-vis conventional deformation techniques and promotes cost and energy efficiency through recycling industrial metal swarf, which is a significant environmental and economic concern.

A TEM study of the effect of oxygen on nanocavity formation and precipitation in rapid - solidified Fe-16Ni-9Cr stainless steels

1994 ◽  
Vol 52 ◽  
pp. 700-701
Author(s):  
S. Wisutmethangoon ◽  
T. F. Kelly ◽  
J.E. Flinn
Keyword(s):  
Stainless Steels ◽  
High Mobility ◽  
Hot Extrusion ◽  
Extrusion Ratio ◽  
Gas Atomization ◽  
Cavity Formation ◽  
Nucleation Sites ◽  
Heat Treated ◽  
Different Types ◽  
Effect Of Oxygen

Vacancies are introduced into the crystal phase during quenching of rapid solidified materials. Cavity formation occurs because of the coalescence of the vacancies into a cluster. However, because of the high mobility of vacancies at high temperature, most of them will diffuse back into the liquid phase, and some will be lost to defects such as dislocations. Oxygen is known to stabilize cavities by decreasing the surface energy through a chemisorption process. These stabilized cavities, furthermore, act as effective nucleation sites for precipitates to form during aging. Four different types of powders with different oxygen contents were prepared by gas atomization processing. The atomized powders were then consolidated by hot extrusion at 900 °C with an extrusion ratio 10,5:1. After consolidation, specimens were heat treated at 1000 °C for 1 hr followed by water quenching. Finally, the specimens were aged at 600 °C for about 800 hrs. TEM samples were prepared from the gripends of tensile specimens of both unaged and aged alloys.

Role of Aluminium on the Microstructure and Corrosion Behaviour of Magnesium Prepared by Powder Metallurgy Method

2020 ◽  
Vol 17 (3) ◽  
pp. 8206-8213
Author(s):  
J. Alias
Keyword(s):  
Corrosion Resistance ◽  
Powder Metallurgy ◽  
Corrosion Behaviour ◽  
Corrosion Current ◽  
Optical Microscope ◽  
High Reactivity ◽  
Aluminium Content ◽  
Powder Metallurgy Method ◽  
X Ray Diffraction ◽  
Promising Development

Much research on magnesium (Mg) emphasises creating good corrosion resistance of magnesium, due to its high reactivity in most environments. In this study, powder metallurgy (PM) technique is used to produce Mg samples with a variation of aluminium (Al) composition. The effect of aluminium composition on the microstructure development, including the phase analysis was characterised by optical microscope (OM), scanning electron microscopy (SEM) and x-ray diffraction (XRD). The mechanical property of Mg sample was performed through Vickers microhardness. The results showed that the addition of aluminium in the synthesised Mg sample formed distribution of Al-rich phases of Mg17Al12, with 50 wt.% of aluminium content in the Mg sample exhibited larger fraction and distribution of Al-rich phases as compared to the 20 wt.% and 10 wt.% of aluminium content. The microhardness values were also increased at 20 wt.% and 50 wt.% of aluminium content, comparable to the standard microhardness value of the annealed Mg. A similar trend in corrosion resistance of the Mg immersed in 3.5 wt.% NaCl solution was observed. The corrosion behaviour was evaluated based on potentiodynamic polarisation behaviour. The corrosion current density, icorr, is observed to decrease with the increase of Al composition in the Mg sample, corresponding to the increase in corrosion resistance due to the formation of aluminium oxide layer on the Al-rich surface that acted as the corrosion barrier. Overall, the inclusion of aluminium in this study demonstrates the promising development of high corrosion resistant Mg alloys.

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