Investigation of heat treatment and subsequently surface modification by nano-TiO2 on Mg–Zn–Ca–Mn bio-magnesium alloy

2019 ◽  
Vol 9 (8) ◽  
pp. 931-939 ◽  
Author(s):  
Yandong Yu ◽  
Zehua Yan ◽  
Shiming Bi ◽  
Zhenduo Ma ◽  
Jiahao Qian
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Cleavage Fracture ◽  
Corrosion Potential ◽  
Ceramic Membrane ◽  
Cast Alloy ◽  
Solution Treatment ◽  
Ceramic Film

The microstructure and mechanical properties of Mg–2Zn–0.5Ca–1.0Mn alloy under different treatments were investigated. Nano-TiO2 with biological activity was added to the self-optimized silicate electrolyte in order to enhance the corrosion resistance and the activity of micro-arc oxidation (MAO) coatings formed in the aged bio-magnesium alloy silicate electrolyte. Results show that the tensile strength and micro-hardness of solution treatment alloy were 194 MPa and 40.55 HV, respectively, which were increased by 11% and 30% comparing with as-cast alloy. Subsequently, the experimental alloy was aged at 175 °C from 0.5 h to 36 h, the tensile strength of the alloy reached 229 MPa when the alloy was aged to 16 h, which was 55 MPa higher than the as-cast alloy. Besides, the fracture mechanism transformed from the cleavage fracture to quasi-cleavage fracture after heat treatment. Different content of modified nano-TiO2 (1, 3 and 5 g/L) is added into based silicate electrolyte has been utilized to modify the bio-magnesium coatings for precoated metals. The sealing processes on MAO coatings surface effectively improve the corrosion resistance property of the bio-magnesium alloy. As the concentration of nano-TiO2 increases from 0 g/L to 5 g/L, the corrosion potential of MAO ceramic film increases gradually. When the concentration of nano-TiO2 is 5 g/L, the corrosion potential of the formed ceramic film is the highest, reaching – 1.3601 V, this shows that the ceramic membrane has good corrosion resistance.

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.

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.

TEM Investigations of Electron 21 Magnesium Alloy

2007 ◽  
Vol 130 ◽  
pp. 175-180 ◽  
Author(s):  
Andrzej Kiełbus
Keyword(s):  
Heat Treatment ◽  
Magnesium Alloy ◽  
Solution Heat Treatment ◽  
Cast Alloy ◽  
Solution Treatment ◽  
Air Cooling ◽  
Transmission Electron ◽  
The Matrix ◽  
Cast Condition ◽  
Cast Microstructure

The paper presents results of TEM investigations of Elektron 21 magnesium alloy in as cast condition and after heat treatment. The compositions of the Elektron 21 alloy used in the present study was Mg-2,7%wtNd-1,2%wtGd-0,47%wtZr. Solution heat treatment was performed at 520°C/8 h/water. Ageing treatments were performed at 200°C/4÷96h and 300°C/48h with cooling in air. The as-cast microstructure and microstructural evolution during heat treatment were examined by transmission electron microscopy. Samples were prepared using Gatan PIPS ion mill. Examinations were performed in a JEM 2010 ARP microscope. The microstructure of the cast alloy consists of a-Mg phase matrix with precipitates of Mg12(Ndx,Gd1-x) phase at grain boundaries. After solution treatment the Mg12(Ndx,Gd1-x) phase dissolved in the matrix. The ageing treatment applied after solution treatment with air-cooling caused precipitation of a β’ and β phases.

Effect of Heat Treatment on the Corrosion Resistance of Cast Mg-7.3Al Alloy

2010 ◽  
Vol 146-147 ◽  
pp. 585-588
Author(s):  
Su Qiu Jia ◽  
Guo Jun Liu ◽  
Qi Shuang Chen
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Microstructural Characterization ◽  
Main Role ◽  
Β Phase

Mg-7.3Al magnesium alloys were investigated in the paper. The paper presents microstructural characterization of Mg-7.3Al alloy after casting and heat treatment. The casting temperature was 740°C and heat treatment was performed at 420 °C for 24 h with aging at 180 °C for 8h,16h,24h. The microstructure of the casting alloy consists of α-Mg phase matrix with a primary β phase (Mg17Al12) at grain boundaries. After solution treatment β phases were soluted in α-Mg phase matrix . Aging treatment caused β phases precipitation. The corrosion resistance of magnesium alloy was determined in 3.5 % NaCl by immersion tests and polarization curves. The results shows that the corrosion resistance of magnesium alloy after solution treat is the best than that of the others heat treatment in polarization curve tests and the samples with aging for 16h and 24h presents higher corrosion resistance than those with solution and aging for 8h in immersion tests. Solution treatment plays a main role for corrosion resistance of Mg-7.3Al magnesium alloy in short term corrosion, but more continuous β phases in Mg-7.3Al alloy after ageing act as a barrier and play a main role in long term corrosion.

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.

ALUMINUM 3004

Alloy Digest ◽  
1974 ◽  
Vol 23 (4) ◽  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Shear Strength ◽  
High Temperature ◽  
Magnesium Alloy ◽  
Cold Working ◽  
Heat Treating ◽  
Temperature Performance ◽  
Good Workability ◽  
Manganese Magnesium

Abstract ALUMINUM 3004 is nominally an aluminum-manganese-magnesium alloy which cannot be hardened by heat treatment; however, it can be strain hardened by cold working. It has higher strength than Aluminum 3003 and good workability, weldability and resistance to corrosion. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive and shear strength as well as fatigue. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Al-51. Producer or source: Various aluminum companies. Originally published June 1957, revised April 1974.

Strength of Commercial Aluminum Alloys after Equal Channel Angular Pressing and Post-ECAP Processing

2006 ◽  
Vol 114 ◽  
pp. 91-96 ◽  
Author(s):  
Maxim Yu. Murashkin ◽  
M.V. Markushev ◽  
Julia Ivanisenko ◽  
Ruslan Valiev
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Aluminum Alloys ◽  
Ultimate Tensile Strength ◽  
Equal Channel Angular Pressing ◽  
Room Temperature ◽  
Solution Treatment ◽  
Ecap Processing ◽  
Angular Pressing

The effects of equal channel angular pressing (ECAP), further heat treatment and rolling on the structure and room temperature mechanical properties of the commercial aluminum alloys 6061 (Al-0.9Mg-0.7Si) and 1560 (Al-6.5Mg-0.6Mn) were investigated. It has been shown that the strength of the alloys after ECAP is higher than that achieved after conventional processing. Prior ECAP solution treatment and post-ECAP ageing can additionally increase the strength of the 6061 alloy. Under optimal ageing conditions a yield strength (YS) of 434 MPa and am ultimate tensile strength (UTS) of 470 MPa were obtained for the alloy. Additional cold rolling leads to a YS and UTS of 475 and 500 MPa with 8% elongation. It was found that the post-ECAP isothermal rolling of the 1560 alloy resulted in the formation of a nano-fibred structure and a tensile strength (YS = 540 MPa and UTS = 635 MPa) that has never previously been observed in commercial non-heat treatable alloys.

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