Effective Dispersion of CNTs to Fabricate CNT/Mg Nanocomposite

2015 ◽  
Vol 816 ◽  
pp. 470-475 ◽  
Author(s):  
Guo Qiang Han ◽  
Wen Bo Du ◽  
Zhao Hui Wang ◽  
Ke Liu ◽  
Shu Bo Li ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Yield Strength ◽  
Grain Refinement ◽  
Melting Process ◽  
Az31 Alloy ◽  
Alloy Matrix ◽  
Dispersion Process ◽  
Wet Process ◽  
Magnesium Alloy Az31 ◽  
Effective Dispersion

An effective dispersion process to cast CNT-reinforced in a concentrated magnesium alloy (AZ31) nanocomposite was investigated in this study. The metal magnesium powder was first coated with dispersed CNTs by wet process, followed by the fabricating of CNT/Mg precursor using mechanical briquetting and extrusion. The resultant precursor was then added into AZ31 alloy during the melting process. Finally, CNT/Mg nanocomposites with grain refinement matrix composite were fabricated in as-cast and as-extruded. Compared with the commercial AZ31 alloy, CNT/Mg nanocomposites exhibited higher yield strength of 270 MPa with an increase of 22.7%, which can be largely ascribed to the effective dispersion process of CNTs in the alloy matrix, and the elongation is no significant decrease.

Magnesium Alloy AZ31 - Short Carbon Fiber Composite Obtained by Pressure Die Casting

2015 ◽  
Vol 229 ◽  
pp. 115-122 ◽  
Author(s):  
Anita Olszówka-Myalska ◽  
Jerzy Myalski
Keyword(s):  
Magnesium Alloy ◽  
Carbon Fibers ◽  
Fiber Composite ◽  
Die Casting ◽  
Az31 Alloy ◽  
Chamber Pressure ◽  
Alloy Az31 ◽  
Magnesium Alloy Az31 ◽  
Pressure Die Casting ◽  
Short Carbon

The application of short carbon fibers in magnesium alloy AZ31 matrix composite fabrication by cold chamber pressure die casting was presented. A technological procedure of small-sized and complex-shaped composite casts manufacturing was shown. The microstructure of the composite was characterized as well as its mechanical properties, friction coefficient and wear resistance. The application of mechanical stirring of melted AZ31 alloy with short fibers and then AZ31-Cf suspension pressure die casting ensured obtaining casts with the reinforcing phase correctly distributed and well bonded with the matrix. Comparision of the AZ31-Cf composite with the AZ31 alloy properties, cast in the same conditions, revealed a considerable increase in bending strength and hardness, and some improvement of ductility and sliding friction parameters as a result of short carbon fibers application.

Grain Refinement of Magnesium Alloy AZ31 under Torsion Extrusion with a Square-Hole Die

2010 ◽  
Vol 654-656 ◽  
pp. 711-714 ◽  
Author(s):  
Susumu Mizunuma ◽  
Takamichi Iizuka ◽  
Kazuhiro Mitsui ◽  
Hidehito Okumura ◽  
Masahide Kohzu
Keyword(s):  
Magnesium Alloy ◽  
Grain Refinement ◽  
Cross Section ◽  
Crystal Orientation ◽  
Electron Backscatter Diffraction ◽  
Entire Cross Section ◽  
Extrusion Axis ◽  
Alloy Az31 ◽  
Magnesium Alloy Az31 ◽  
Square Hole

Grain refinement and crystal orientation of magnesium alloy AZ31 under torsion extrusion with a square-hole die are investigated. The optimum temperature and ratio of the die rotation speed to the extrusion speed were clarified, resulting in uniformly distributed fine grains with sizes in the range 1- m over the entire cross section of the worked specimen. The crystal orientation of the specimen was determined by electron backscatter diffraction and compared with that of a conventionally extruded specimen. In the case of torsion extrusion, a very strong <0001> texture was observed along the extrusion axis, especially in the center region of the cross section. In contrast, the <0001> direction of many grains in the conventionally extruded specimen tended to be perpendicular to the extrusion axis.

Influence of number of ECAP passes on microstructure and mechanical properties of AZ31 magnesium alloy

2012 ◽  
Vol 57 (3) ◽  
pp. 711-717 ◽  
Author(s):  
K. Bryła ◽  
J. Dutkiewicz ◽  
L. Litynska-Dobrzynska ◽  
L.L. Rokhlin ◽  
P. Kurtyka
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Grain Refinement ◽  
Vickers Microhardness ◽  
Az31 Alloy ◽  
Az31 Magnesium Alloy ◽  
Angular Pressing ◽  
Microstructure And Mechanical Properties ◽  
Transmission Electron

The aim of this work was to investigate the influence of the number of equal channel angular pressing (ECAP) passes on the microstructure and mechanical properties of AZ31 magnesium alloy. The microstructure after two and four passes of ECAP at 423 and 523 K was investigated by means of optical and transmission electron microscopy. The mechanical properties were carried out using Vickers microhardness measurements and compression test. The grain refinement in AZ31 alloy was obtained using ECAP routes down to 1,5 μm at 423 K. Processes of dynamic recrystallization during ECAP were observed. It was found that a gradual decrease of grain size occurs with the increasing of number of ECAP passes. The grain refinement increases mechanical properties at ambient temperature, such as Vickers microhardness and compression strength proportionally to d-0.5.

Corrosion Behaviors of Fluoride Treated Cast Magnesium Alloy in Hank’s Solution

2016 ◽  
Vol 852 ◽  
pp. 113-119
Author(s):  
Chun Yan Zhang ◽  
Ming Bo Yang ◽  
Cheng Long Liu
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Az31 Alloy ◽  
Second Phase ◽  
Magnesium Alloy Az31 ◽  
Corrosion Behaviors ◽  
Second Phases ◽  
Cast Magnesium Alloy ◽  
Cast Magnesium ◽  
Hank’S Solution

Fluoride conversion films were synthesized on cast magnesium alloy AZ31 by immersion in hydrofluoric acid for different days to improve the corrosion resistance of Mg alloys as degradable implant material. The effects of the films on the corrosion behavior of the mg substrates were investigated by immersion tests. The results showed the fluoride conversion film was affected by the distribution of the chemical component of cast AZ31 alloy and the film on the second phases has more pores and micro-crack, but the bottoms of the pores were also covered by the conversion film and the substrate was not exposed through the pores. The fluoride conversion coatings significantly improved the corrosion resistance of cast AZ31 alloy. The film on the second phase with more pores is the first to dissolve. The most improved corrosion protection was achieved by 15 days treatment with the thickest film in terms of hydrogen evolution rate and damage morphology.

Potentiodynamic Tests of Magnesium Alloy AZ31 with Lithium Additive

2013 ◽  
Vol 211 ◽  
pp. 93-100
Author(s):  
Joanna Przondziono ◽  
Witold Walke ◽  
Eugeniusz Hadasik ◽  
Stanisław Lalik
Keyword(s):  
Magnesium Alloy ◽  
Electrochemical Corrosion ◽  
Corrosion Current ◽  
Az31 Alloy ◽  
Chloride Ions ◽  
Molar Concentration ◽  
Lithium Content ◽  
Nacl Solution ◽  
Alloy Az31 ◽  
Magnesium Alloy Az31

The purpose of the study is to assess electrochemical corrosion resistance of magnesium alloy AZ31 with additives of 4.5, 7.5 and 15 % lithium in NaCl solutions. Corrosion tests were performed in solutions with concentration 0.01 2 M NaCl with application of electrochemical testing system VoltaLab®PGP201. Resistance to electrochemical corrosion was evaluated on the ground of registered anodic polarisation curves by means of potentiodynamic method. Results of performed tests show unequivocally deterioration of corrosion characteristics of the alloy together with increase of molar concentration of NaCl solution. As chloride ions concentration increases, decrease of corrosion potential and polarisation resistance, as well as increase of corrosion current density are observed. Deterioration of corrosion characteristics of AZ31 alloy was shown with the increase of lithium content. It must be highlighted that irrespective of molar concentration of NaCl solution, there is also presence of pitting corrosion in the tested alloy. It proves that magnesium alloy AZ31-Li is not resistant to that type of corrosion. Test results prove that it is necessary to apply protective films on elements made of magnesium alloy with lithium additive.

Influence of Silane on Corrosion Performance of Silane-Modified Acrylate Interpenetrating Polymer Network Coating on Magnesium Alloy AZ31

2011 ◽  
Vol 686 ◽  
pp. 186-191
Author(s):  
Rong Chang Zeng ◽  
Chen Lan Liu ◽  
Ling Hong Kong ◽  
Hong Zhi Cui
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Salt Spray ◽  
Polymer Network ◽  
Az31 Alloy ◽  
Interpenetrating Polymer Network ◽  
Neutral Salt ◽  
Corrosion Performance ◽  
Alloy Az31 ◽  
Magnesium Alloy Az31

The possibility that various silane treatments may enhance the corrosion resistance of a magnesium alloy AZ31 with silane-modified acrylate interpenetrating polymer network (IPN) coating has been investigated. Potentiodynamic electrochemical tests and neutral salt spray test were applied to evaluate the corrosion performance of the alloy. The results show that silane film improves corrosion resistance of the AZ31 alloy with and without IPN coating. The silane-modified IPN coatings improved more than 4 orders of magnitude of the corrosion resistance of the substrate.

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