Indirect improvement of high temperature mechanical properties of a Mg-based alloy Elektron21 by addition of AlN nanoparticles (original) (raw)
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Materials (Basel, Switzerland), 2017
In the current work, a novel magnesium alloy Elektron21 reinforced by ceramic AlN nanoparticles were produced by an ultrasound-assisted casting. The fabricated nanocomposites were investigated to evaluate their microstructure, hardness, physical, thermal and electrical conductivity. The microstructural evolutions show that a uniform dispersion of the ceramic particles within the matrix can be achieved by employing the ultrasound-assisted stirring. However, some nanoparticles were found to be pushed by the solidification front. According to the Vickers hardness results, the addition of AlN nanoparticles results in a slight improvement of the mechanical properties of the nanocomposites. What is surprising is that both electrical and thermal conductivity of the nanocomposite were improved significantly as a consequence of AlN addition. This improvement in the conductivity characteristics of the nanocomposite is mainly corresponding to the structural effect of nanoparticles within the m...
Metals, 2019
A pure Mg and a ZW0303 alloy metal matrix nanocomposite reinforced with AlN nanoparticles were prepared assisted by mechanical stirring and sonication for deagglomeration of particles. The produced nanocomposites were investigated to determine the influence of the AlN nanoparticles during indirect extrusion on the microstructure and texture development, as well as the resulting hardness and mechanical properties. For pure Mg, grain refinement and hardness increase due to the addition of AlN were revealed in the as-cast and the extruded condition. For ZW0303, the same was found for the as-cast condition. However, contamination of the alloy with Al significantly changes the recrystallization behavior during extrusion. This is directly related to the removal of solute Y due to the formation of intermetallic particles. Particle and grain size effects were distinguished for this alloy.
JOM, 2019
Elektron21 (E21) and its composites with additions of 0.25 wt.%, 0.5 wt.%, and 1 wt.% AlN/Al nanoparticles (NPs) were fabricated by a high shear dispersion technology. Their creep properties were investigated over a stress range between 80 MPa and 140 MPa at 240°C. The grain size exhibits an obvious increase with the addition of AlN/Al NPs compared with the monolithic E21 alloy. Increasing the content of AlN/Al NPs leads to a pronounced improvement of creep resistance. Microstructural analysis shows that, with the addition of 1% AlN/Al NPs in E21, the distribution of the intermetallics Mg 3 RE becomes much more homogeneous and their size is reduced. Such Mg 3 RE particles can prevent the dislocation slip more efficiently during creep. Besides these Mg 3 RE particles, the additional formation of Al 2 RE and Al 2 Zr 3 phases, which results from the reactions of AlN/Al NPs and the alloying elements Zr and REs, could act as thermal stable particles to improve the creep resistance. Finally, the remained AlN NPs without reactions are beneficial for the improvement of the creep resistance to some extent due to Orowan strengthening. JOM
Eff ect of Nano Al 2 O 3 Particle Addition on the Mechanical Properties of Mg-5 Sn Alloy
2018
In this study Mg-5Sn alloy was reinforced with 1 and 2 volume % alumina particles of sizes smaller than 1 micron using cold pressure die casting in order to produce a higher strength Mg-5Sn alloy matrix composite. Microstructural analysis of the alloy and the composite was carried out using XRD and Scanning Electron Microscopy (SEM). Mechanical properties were evaluated through tensile tests and hardness measurements. It was found that addition of nano-Al2O3 particles to the Mg-6Sn alloy improved the mechanical properties. XRD results show the presence of both Mg2Sn phase and Al2O3 particles in the Mg rich matrix.
High temperature mechanical properties of AlMgZn alloys with copper and zirconium additions
Le Journal de Physique IV, 1993
High temperature mechanical properties of AlMgZn alloys grain refined by zirconium were investigated by impression creep and tensile tests. The strain rate sensitivities and activation energies obtained are presented. It has been found that the steady-state impression creep rate is strongly influenced by Cu and Zr addition. The simultaneous addition of Cu and Zr resulted in fine-grained microstructure due to which the material exhibited superplastic properties at high temperatures. Together with the superplastic behaviour the occurrence of a threshold stress has also been observed.
Effect of copper and zirconium upon the high temperature mechanical properties of AlMgZn alloys
Physica Status Solidi (a), 1993
High temperature mechanical properties of AlMgZn alloys are investigated by impression creep tests and the strain rate sensitivities and activation energies obtained are presented. It is found that the steady-state impression creep rate is strongly influenced by Cu and Zr addition. The simultaneous addition of Cu and Zr results in a fine-grained microstructure due to which the material exhibits superplastic properties at high temperatures. Together with the superplastic behaviour the occurrence of a threshold stress is also proved. On the contrary, if the deformation is not superplastic, threshold strcsses are not observable. It is shown that the relatively high apparent activation enthalpy obtained for thc superplastic region of deformation is due to the strong temperature dependence of the threshold stress, and taking into account this fact a true activation enthalpy corresponding to that of the bulk diffusion can be assessed. *) In honour of Prof. em. Dr. H. LOFFLER'S 70th birthday.
Effect of Magnesium Content on the Mechanical Properties of Al-Zn-Mg Alloys
Nowadays various kinds of aluminium alloys are utilized widely in different types of manufacturing industries, like automobile, aerospace etc. It is very difficult to find any other metallic element that can be used in so many ways. Aluminium can be used in its pure form or in the form of an alloy by combining it with a variety of other elements like Copper, Magnesium, Manganese, Silicon, and Zinc etc. Each element imparts different characteristics to the alloy and their composition has a varying effect on the mechanical properties of the alloy [1]. This project is aimed at studying the effect of varying the composition of Magnesium on the mechanical properties like strength and hardness in an Aluminium-Zinc-Magnesium alloy. Sand casting was used for the purpose of the project and testing was done on the samples for determining the resultant mechanical properties.
Materials, 2019
Laboratory-scale sheets of 5182-type AlMgMn alloys with varying Mg and Mn contents and additions of different amounts of Zn, Cu, Zr and Er were studied. The sheets were produced using two different cold-rolling degrees and two soft-annealing treatment procedures: air-circulated furnace annealing at 370°C with subsequent furnace cooling, and salt-bath annealing with subsequent water quenching. Mechanical properties and deformation surface quality were studied via tensile tests with simultaneous visual surface characterization. The influence of the chemical composition and the processing route on grain size, mechanical properties, and surface quality is discussed in the study. A reduction in the Mg content improves the surface quality after plastic deformation, but at the expense of the mechanical properties. The results suggest the presence of an optimum Mn content in terms of optical appearance and mechanical properties. Adding Zr largely inhibits recrystallization, which is reflected in a textured microstructure. Adding Er affects neither the surface quality nor the mechanical properties. Specific combinations of Zn or Cu addition, cold-rolling degree, and heat treatment generate significant improvements in the mechanical and optical properties. In general, annealing at high temperature with subsequent quenching leads to enhanced surface quality and mechanical properties, and adding Zn enables further noteworthy improvements.
The effect of Mg content on microstructure in Al-12wt. %Zn-x Mg Alloy
Journal of Applied Research and Technology
The effect of adding different Mg contents to an Al12wt.%Zn master alloy was experimentally investigated. The AlZnMg alloys were unidirectionally solidified as a function of solidification parameters, temperature gradient GL, solidification front velocity V, and composition C0. The alloys were solidified with a constant temperature gradient (GL=2500K/m) in the solidification front velocity range from 4X106m/s to 1.7X104m/s. The resulting microstructure was characterized to investigate the effect of solidification front velocities and composition on primary dendrite arm spacing, volume percentage of eutectic in interdendritic regions and τ intermetallic phase in αAl matrix. Theoretical models for the dendrite arm spacing and dendrite tip radius have been compared with the experimental observations.
Nano-ZnO Particles’ Effect in Improving the Mechanical Response of Mg-3Al-0.4Ce Alloy
Metals, 2016
Magnesium based nanocomposites, due to their excellent dimensional stability and mechanical integrity, have a lot of potential to replace the existing commercial Al alloys and steels used in aerospace and automotive applications. Mg-Al alloys are commercially used in the form of AZ (magnesium-aluminum-zinc) and AM (magnesium-aluminum-manganese) series in automobile components. However, the Mg 17 Al 12 phase in Mg-Al alloys is a low melting phase which results in a poor creep and high temperature performance of the alloys. Rare earth additions modify the phase and hence improve the properties of the materials. In this paper, Ce and nano ZnO particles were added to Mg-Al alloys to attain a favorable effect on their properties. The developed materials exhibited promising properties in terms of thermal expansion coefficient (CTE), hardness, and tensile strength. Further, the ZnO addition refined the microstructure and helped in obtaining a uniform distribution, however without grain size refinement. The increased addition of ZnO and the improvement in the distribution led to an enhancement in the properties, rendering the materials suitable for a wide spectrum of engineering applications.