scholarly journals Effect of Modification on Microstructure and Properties of AZ91 Magnesium Alloy

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 536
Author(s):  
Andrzej Kiełbus ◽  
Robert Jarosz ◽  
Adam Gryc
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Magnesium Alloy ◽  
Volume Fraction ◽  
Az91 Alloy ◽  
Carbon Powder ◽  
Az91 Magnesium Alloy ◽  
Microstructure And Properties ◽  
Az91 Magnesium ◽  
Cast Magnesium

Refinement of α-Mg solid solution grains has a significant influence on the improvement of mechanical properties of cast magnesium alloys. In the article, the effects of three modifiers on microstructure and properties of AZ91 magnesium alloy casted to a sand mould were described. Overheating, hexachloroethane and wax-CaF2-carbon powder were applied. The research procedure comprised microstructure analysis by means of light microscopy, scanning electron microscopy and quantitative analysis with AnalySIS Pro® software and mechanical properties’ investigation. The microstructure of AZ91 alloy in the as-cast condition consists of α-Mg solid solution with precipitates of Mg17Al12, Mg2Si and Al8Mn5 phases. It was reported that all applied modifiers cause refinement of α-Mg solid solution grains and a decrease of the volume fraction of α-Mg+Mg17Al12 compound discontinuous precipitates. The best results were obtained in the case of wax-CaF2-carbon powder.

Effects of CaCO3 Modificator on Microstructure and Mechanical Properties of Cast AZ91 Magnesium Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 155-158
Author(s):  
Qu Dong Wang ◽  
Yang Zhao ◽  
Qing Hua Li
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Cleavage Fracture ◽  
Tensile Fracture ◽  
Az91 Alloy ◽  
Az91 Magnesium Alloy ◽  
Microstructure And Mechanical Properties ◽  
Reticular Structure ◽  
Az91 Magnesium ◽  
Alloy Increase

Effects of CaCO3 modificator on microstructure and mechanical properties of cast AZ91 Magnesium alloy have been investigated. Tensile fracture behavior of AZ91 alloys modified by CaCO3 has also been studied. Results show that CaCO3 modificator can obviously refine the grain of AZ91 magnesium alloy and Mg17Al12. Mg17Al12 in grain boundary of AZ91 alloy after modified by CaCO3 changes from continuous reticular structure to discontinuous reticular structure, even so much as granular structure and rod structure. After modified by 0.5wt% CaCO3 modificator, ultimate tensile strength, yield strength, impact toughness and elongation of AZ91 alloy increase from 186MPa to 200MPa, from 147MPa to 160MPa, from 4J to 9J and from 2.6% to 5%, respectively. And 0.5wt% CaCO3 modificator brings about an optimal refining effect. The study also shows that the fracture mechanism of modified AZ91 alloy is between cleavage fracture and quasi-cleavage fracture, which is as same as that of unmodified AZ91 alloy.

scholarly journals Effect of Samarium on the Microstructure and Corrosion Resistance of AZ91 Magnesium Alloy Treated by Ultrasonic Vibration

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2331 ◽  
Author(s):  
Yang Chen ◽  
Zheng Yin ◽  
Hong Yan ◽  
Guo-Hua Zhou ◽  
Xiao-Quan Wu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Magnesium Alloy ◽  
Ultrasonic Vibration ◽  
Volume Fraction ◽  
Galvanic Corrosion ◽  
Corrosion Current ◽  
Az91 Alloy ◽  
Uniform Corrosion ◽  
Az91 Magnesium Alloy ◽  
Az91 Magnesium

The effects of samarium (Sm) on the microstructure and corrosion behavior of AZ91 magnesium alloy treated by ultrasonic vibration were investigated by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and electrochemical measurements. The results showed that the addition of Sm resulted in the formation of Al2Sm, which reduced the volume fraction of the β-Mg17Al12 phase and changed its morphology to fine granular. The AZ91–Sm alloys treated by ultrasonic vibration revealed relatively lower weight loss, hydrogen evolution, and corrosion current density values compared to the ultrasonic-treated AZ91 alloy prepared without Sm. Locally, a coarse β phase in the ultrasonic-treated AZ91 alloy accelerated the possibility of micro-galvanic corrosion growing into the matrix. In the prepared AZ91–Sm alloys treated by ultrasonic vibration, the fine β and Al2Sm phases reduced the probability of micro-galvanic corrosion growth and, therefore, formed a uniform corrosion layer on the surface of the alloys.

Effects of La on the Microstructures and Mechanical Properties of AZ91 Magnesium Alloy and its Mechanism

2011 ◽  
Vol 328-330 ◽  
pp. 1650-1653 ◽  
Author(s):  
Jin Ling Zhang ◽  
She Bin Wang ◽  
Xiao Ye Qi ◽  
Bing She Xu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Magnesium Alloy ◽  
Yield Strength ◽  
Maximum Yield ◽  
Az91 Alloy ◽  
Strengthening Effect ◽  
Az91 Magnesium Alloy ◽  
Az91 Magnesium ◽  
Maximum Yield Strength

Microstructure changes brought by the addition of La element to AZ91 magnesium alloy are studied, also, the precipitating phases were identified and their influence on the mechanical properties of alloys was investigated. Results show La makes refinement of microstructure of the AZ91 alloy, and decrease the size of Mg17Al12 phase. La element takes a priority to react with Al element over Mg, forming binary phase Al11La3 with high melting point. Certain amount of La increases tensile strength, yield strength and elongation. With more addition, La would combine more Al in matrix and decrease strengthening effect, because Al11La3 phase would become coarsening. The mechanical poroerties tests indicate that AZ91+0.16%La alloy has the best properties. Maximum tensile strength, maximum yield strength and elongation are 245MPa, 178MPa and 14.5% respective, increased by 21%, 19% and 48% respectively. The mechanism of La strenthing mechanical properties is proposed that Al11La3 phase enriched on solid-liquid interface, increased the degree of supercooling, refined the grain size and changed the crystal style.

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.

scholarly journals Investigation of the Influence of Open-Die Forging Parameters on the Flow Kinetics of AZ91 Magnesium Alloy

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4010
Author(s):  
Grzegorz Banaszek ◽  
Teresa Bajor ◽  
Anna Kawałek ◽  
Tomasz Garstka
Keyword(s):  
Magnesium Alloy ◽  
Operation Time ◽  
Strength Properties ◽  
Hydraulic Press ◽  
Az91 Alloy ◽  
Az91 Magnesium Alloy ◽  
Numerical Tests ◽  
Az91 Magnesium ◽  
Product Manufacturing ◽  
Open Die Forging

This paper presents the results of numerical tests of the process of forging magnesium alloy ingots (AZ91) on a hydraulic press with the use of flat and proprietary shaped anvils. The analysis of the hydrostatic pressure distribution and the deformation intensity was carried out. It is one of the elements used for determining the assumptions for the technology of forging to obtain a semi-finished product from the AZ91 alloy with good strength properties. The aim of the research was to reduce the number of forging passes, which will shorten the operation time and reduce the product manufacturing costs. Numerical tests of the AZ91 magnesium alloy were carried out using commercial Forge®NxT software.

Enhanced mechanical properties of AZ91 magnesium alloy by inoculation and hot deformation

2021 ◽  
Vol 802 ◽  
pp. 140667
Author(s):  
Mohammad Sajad Mehranpour ◽  
Ali Heydarinia ◽  
Massoud Emamy ◽  
Hamed Mirzadeh ◽  
Ali Koushki ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Hot Deformation ◽  
Az91 Magnesium Alloy ◽  
Az91 Magnesium

scholarly journals Structural Aspects of Remelting of the AZ91 Magnesium Alloy Surface Layer

2016 ◽  
Vol 16 (1) ◽  
pp. 13-18
Author(s):  
J. Iwaszko ◽  
M. Strzelecka
Keyword(s):  
Surface Layer ◽  
Magnesium Alloy ◽  
Structural Changes ◽  
Continuous Wave ◽  
Sample Surface ◽  
Alloy Surface ◽  
Az91 Alloy ◽  
Az91 Magnesium Alloy ◽  
Az91 Magnesium ◽  
Alloy Surface Layer

Abstract In this study, modification of the AZ91 magnesium alloy surface layer with a CO2 continuous wave operation laser has been taken on. The extent and character of structural changes generated in the surface layer of the material was being assessed on the basis of both macro- and microscopy investigations, and the EDX analysis. Considerable changes in the structure of the AZ91 alloy surface layer and the morphology of phases have been found. The remelting processing was accompanied by a strong refinement of the structure and a more uniform distribution of individual phases. The conducted investigations showed that the remelting zone dimensions are a result of the process parameters, and that they can be controlled by an appropriate combination of basic remelting parameters, i.e. the laser power, the distance from the sample surface, and the scanning rate. The investigations and the obtained results revealed the possibility of an effective modification of the AZ91 magnesium alloy surface layer in the process of remelting carried out with a CO2 laser beam.

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