Microstructural Changes of AZ91 Magnesium Alloy After Heat Treatment

Magnesium ◽  
2005 ◽  
pp. 196-201 ◽  
Author(s):  
Andrzej Kiełbus ◽  
Lubomir Ciżek ◽  
Libor Pawlica
Keyword(s):  
Heat Treatment ◽  
Magnesium Alloy ◽  
Az91 Magnesium Alloy ◽  
Microstructural Changes ◽  
Az91 Magnesium

Effects of heat treatment on the wear behavior of surfacing AZ91 magnesium alloy

2017 ◽  
Vol 32 (11) ◽  
pp. 2161-2168 ◽  
Author(s):  
Qingqiang Chen ◽  
Kaiyue Li ◽  
Yuyang Liu ◽  
Zhihao Zhao ◽  
Kai Tao ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Magnesium Alloy ◽  
Wear Behavior ◽  
Az91 Magnesium Alloy ◽  
Az91 Magnesium ◽  
Image Position

Abstract

Ceria Coatings Prepared by Sol-Gel Approach on AZ91 Magnesium Alloy

2017 ◽  
Vol 898 ◽  
pp. 1369-1380 ◽  
Author(s):  
Hui Min Han ◽  
Dan Tong Wang ◽  
Hua Qian Yu ◽  
Min Zuo ◽  
Li Hong Wang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Sol Gel ◽  
Electrochemical Corrosion ◽  
Chemical Conversion ◽  
Corrosion Current ◽  
Az91 Alloy ◽  
Az91 Magnesium Alloy ◽  
Az91 Magnesium

The ceria coatings on AZ91 substrates were successfully synthesized by chemical conversion and the corrosion resistance of AZ91 samples with and without ceria coatings were evaluated by means of electrochemical corrosion in 3.5 wt.% NaCl solution. According to the parameters derived from the polarization date, the Icorr (the corrosion current density) values of the coated samples are smaller than that of bare one, indicating that the corrosion resistance of AZ91 alloys has been improved to some extent. The influence of fluoridated pretreatment, inter-layer heat treatment, sintering temperature and the layer of films on the performance of ceria coatings were also investigated. It was found that the inter-layer heat treatment has no influence on improving the anticorrosion resistance of AZ91 alloy. In comparison with the bare one, the Icorr of optimal sample is about 0.0219mA/cm2, which decreases by two orders of magnitude, indicating that the ceria coatings could significantly improve the corrosion resistance of AZ91 magnesium alloy.

Corrosion Resistance of Al-12Si Coatings on AZ91 Magnesium Alloy Prepared through Flame Spray

2013 ◽  
Vol 765 ◽  
pp. 639-643 ◽  
Author(s):  
Pei Hu Gao ◽  
Jian Ping Li ◽  
Zhong Yang ◽  
Yong Chun Guo ◽  
Yan Rong Wang
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Coating Thickness ◽  
Corrosion Potential ◽  
Treatment Temperature ◽  
Phase Changes ◽  
Flame Spray ◽  
Az91 Magnesium Alloy ◽  
Az91 Magnesium

In this study, Al-12Si alloy coatings with different thickness were prepared through flame spray on the surface of the AZ91 magnesium alloy to improve its corrosion resistance. The corrosion resistance was characterized through corrosion potential using electrochemical methods. The Al-12Si alloy coatings were heat treated at 100 °C, 200 °C and 300 °C for 6, 12, 18 and 24 hours. The effects of heat treatment temperature and time on the coatings’ corrosion resistance were discussed. It was found that there were no phase changes during the deposition of Al-12Si coatings through flame spray and heat treatment. The greater the coating thickness was, the higher the corrosion potential was. After annealing, the inner microstructure of the Al-12Si coating was densified furtherly and the annealed coatings had higher corrosion potential and better corrosion resistance. The coating annealed at 100 °C for 18 hours had the highest corrosion potential and the best corrosion resistance in the same coating thickness.

scholarly journals Effects Of Aluminum Sputtering On The Corrosion Resistance Of AZ91 Alloy

2015 ◽  
Vol 60 (2) ◽  
pp. 953-955 ◽  
Author(s):  
Y. Ishibashi ◽  
M. Nose ◽  
M. Hatakeyama ◽  
S. Sunada
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Az91 Alloy ◽  
Az91 Magnesium Alloy ◽  
Eds Analysis ◽  
Heat Treated ◽  
Film Forming ◽  
Az91 Magnesium ◽  
Aluminium Film

Abstract The corrosion resistance of a Magnesium alloy is low and needs to be improved. This research aimed at corrosion-resistance improvement by supatterd deposition aluminium film, which is formed on the surface of AZ91 Magnesium-alloy. Corrosion resistance performed polarization curve measurement, was evaluated in quest of the corrosion rate using the Tafel extrapolation method, and conducted surface observation and EDS analysis by SEM. Although corrosion resistance is not improved only by film forming because of defects in film, corrosion resistance is improved by heat treatment for 3 hours by 553K after sputtering. In the case of heat treated at 623K and 673K for 3 hours, magnesium diffuses through the alminium film and reached the surface of the film. Thus, heat treatment at high temperature degrade the corrosion resistance of the film. The optimization of heat treatment after sputtering is important in this method.

Precipitation behaviors of spray formed AZ91 magnesium alloy during heat treatment and their strengthening effect

2009 ◽  
Vol 30 (3) ◽  
pp. 440-444 ◽  
Author(s):  
Jin-feng Huang ◽  
Hong-yan Yu ◽  
Yong-bing Li ◽  
Hua Cui ◽  
Jian-ping He ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Magnesium Alloy ◽  
Strengthening Effect ◽  
Az91 Magnesium Alloy ◽  
Az91 Magnesium

Effects of Hot Extrusion and Heat Treatment on Mechanical Properties and Microstructures of AZ91 Magnesium Alloy

2012 ◽  
Vol 562-564 ◽  
pp. 242-245 ◽  
Author(s):  
Ming Tan ◽  
Zhao Ming Liu ◽  
Gao Feng Quan
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Magnesium Alloy ◽  
Solution Treatment ◽  
Annealing Treatment ◽  
Aging Treatment ◽  
Az91 Alloy ◽  
Az91 Magnesium Alloy ◽  
Az91 Magnesium

The effects of heat treatment on the microstructure, tensile property and fracture behavior of as-extruded AZ91 magnesium alloy were studied by OM and SEM. The results show that the grain of as-cast AZ91 alloy is refined by extruding and dynamic recrystallization, and the mechanical properties increase obviously. The ductility is significantly enhanced after solution treatment of the as-extruded AZ91 alloy, tensile strength is almost the same before and hardness is significantly reduced after solution treatment and artificial aging treatment. The tensile strength reduced and the ductility is significantly enhanced of as-extruded AZ91 magnesium alloy after annealing processes. The fracture surface of as-extruded AZ91 magnesium alloy has the mixture of ductile and brittle characteristic. But after T6 or annealing treatment, its dimple number increases evidently.

Improvement of high temperature fatigue lifetime in AZ91 magnesium alloy by heat treatment

2013 ◽  
Vol 588 ◽  
pp. 357-365 ◽  
Author(s):  
Mehdi Mokhtarishirazabad ◽  
Mohammad Azadi ◽  
Gholam Hossein Farrahi ◽  
Gerhard Winter ◽  
Wilfred Eichlseder
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Magnesium Alloy ◽  
Az91 Magnesium Alloy ◽  
Fatigue Lifetime ◽  
High Temperature Fatigue ◽  
Az91 Magnesium

Effect of Heat Treatment of AZ91 Magnesium Alloy on the Electroless Ni-P Deposition

2018 ◽  
Vol 1148 ◽  
pp. 122-127 ◽  
Author(s):  
Charu Singh ◽  
S.K. Tiwari ◽  
Raghuvir Singh
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Electrochemical Impedance ◽  
Cast Alloy ◽  
Az91 Magnesium Alloy ◽  
Heat Treated ◽  
Az91 Magnesium ◽  
Electroless Ni

Magnesium alloys are excellent choice for automobile, aerospace, and computer components owing to their light weight, unique physical and mechanical properties. However, poor corrosion resistance has restricted their applications in aggressive environments. The surface coating is one of the viable options to reduce the susceptibility of magnesium alloys to corrosion. The present study focuses on the effect of heat treatment of AZ91 magnesium alloy, for different durations at 400 °C, prior to electroless Ni-P deposition on corrosion resistance. The microstructure and elemental analysis of the heat-treated specimens are performed using SEM and EDS techniques respectively. It is observed that the duration of heat treatment has a significant effect on the surface morphology and microstructure of the alloy. The precipitates in the cast alloy (enriched with Mg and Al) fragmented and the transformed into a new Al and Zn rich phase, after 12 h heat treatment. The dissolution of precipitates, however, observed on heating further to 24 h and exhibited relatively a lesser corrosion current density. The dense electroless Ni-P deposition is formed on the alloy heat treated for 24 h. The corrosion behavior of the single Ni-P layer on the heat treated (for 12 h) and untreated alloy show a marked deterioration, as investigated by the anodic polarization and electrochemical impedance spectroscopy (EIS) techniques. Relatively a better corrosion performance is seen for the double-layer Ni-P deposition. The duplex layer coatings on the as cast and heat treated for 24 h at 400 °C substrates showed an improved corrosion resistance compared to that on the 12 h heat treated substrate.

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