Room temperature deformation of in-situ grown quasicrystals embedded in Al-based cast alloy

An Al-based cast alloy containing Mn, Be and Cu has been chosen to investigate the room temperature deformation behavior of QC particles embedded in Al-matrix. Using LOM, SEM (equipped with EDS), conventional TEM with SAED and controlled tensile and compression tests, the deformation response of AlMn2Be2Cu2 cast alloy at room temperature has been examined. Alloy consisted of Al-based matrix, primary particles and eutectic icosahedral quasicrystalline (QC i-phase) and traces of Θ-Al2Cu and Al10Mn3. Tensile and compression specimens were used for evaluation of mechanical response and behavior of QC i-phase articles embedded in Al-cast alloy. It has been established that embedded QC i-phase particles undergo plastic deformation along with the Al-based matrix even under severe deformation and have the response resembling that of the metallic materials by formation of typical cup-and-cone feature prior to failure. So, we can conclude that QC i-phase has the ability to undergo plastic deformation along with the Al-matrix to greater extent contrary to e.g. intermetallics such as Θ-Al2Cu for instance

Room temperature deformation of in-situ grown quasicrystals embedded in Al-based cast alloy

An Al-based cast alloy containing Mn, Be and Cu has been chosen to investigate the room temperature deformation behavior of QC particles embedded in Al-matrix. Using LOM, SEM (equipped with EDS), conventional TEM with SAED and controlled tensile and compression tests, the deformation response of AlMn2Be2Cu2 cast alloy at room temperature has been examined. Alloy consisted of Al-based matrix, primary particles and eutectic icosahedral quasicrystalline (QC i-phase) and traces of Θ-Al2Cu and Al10Mn3. Tensile and compression specimens were used for evaluation of mechanical response and behavior of QC i-phase articles embedded in Al-cast alloy. It has been established that embedded QC i-phase particles undergo plastic deformation along with the Al-based matrix even under severe deformation and have the response resembling that of the metallic materials by formation of typical cup-and-cone feature prior to failure. So, we can conclude that QC i-phase has the ability to undergo plastic deformation along with the Al-matrix to greater extent contrary to e.g. intermetallics such as Θ-Al2Cu for instance

INFLUENCE OF COOLING RATE AND ALLOYING ELEMENTS ON THE MICROSTRUCTURE OF THE Al-Mn-BASED ALLOY

Aluminum-based alloys have been used extensively for the past five decades primarily due to their good strength vs. specific weight ratio. Numerous methods and techniques have been devised to further improve mechanical properties of these alloys as they are often used in the transport applications. Influence of the cooling rate and chemical composition on the constitution of Al-Mn-based alloy has been investigated. Elements such as B, Be, C, Ca, Cu, Fe, Mg, Si, Sr and Ti have been introduced to Al-Mn alloys in order to study their influence. Changes in cooling rates during casting using permanent copper molds with different sized troughs have also been monitored. Combined influence of changes in chemical composition and cooling rates was followed using LOM, SEM, EDS, DAS measurement and mathematic modeling. It has been established that Al-Mn-based alloys form a lot of different phases during synthesis and solidification, mostly crystalline intermetallics, but also in some cases quasicrystalline (QC) ones, especially when cooling rates exceed 500 Ks-1. QCs are currently also considered as an alternative for reinforcement of Al-Mn-based alloys. It was found that in the case of alloy system Al-Mn-Cu-Be and cooling rates between 500 and 1350 Ks-1 the preferred phase formed was an icosahedral QC phase or iQC. Icosahedral QC phase formed as the primary phase and in some cases also in the form of the quasicrystalline eutectic (αAl + iQC). Additions of B, C, Ca, Ti and Sr have not proven to be effective in promoting formation of quasicrystals in cast Al-Mn alloys whilst Fe, Cu, Mg and Si proved to be highly efficient.Aluminum-based alloys have been used extensively for the past five decades primarily due to their good strength vs. specific weight ratio. Numerous methods and techniques have been devised to further improve mechanical properties of these alloys as they are often used in the transport applications. Influence of the cooling rate and chemical composition on the constitution of Al-Mn-based alloy has been investigated. Elements such as B, Be, C, Ca, Cu, Fe, Mg, Si, Sr and Ti have been introduced to Al-Mn alloys in order to study their influence. Changes in cooling rates during casting using permanent copper molds with different sized troughs have also been monitored. Combined influence of changes in chemical composition and cooling rates was followed using LOM, SEM, EDS, DAS measurement and mathematic modeling. It has been established that Al-Mn-based alloys form a lot of different phases during synthesis and solidification, mostly crystalline intermetallics, but also in some cases quasicrystalline (QC) ones, especially when cooling rates exceed 500 Ks-1. QCs are currently also considered as an alternative for reinforcement of Al-Mn-based alloys. It was found that in the case of alloy system Al-Mn-Cu-Be and cooling rates between 500 and 1350 Ks-1 the preferred phase formed was an icosahedral QC phase or iQC. Icosahedral QC phase formed as the primary phase and in some cases also in the form of the quasicrystalline eutectic (αAl + iQC). Additions of B, C, Ca, Ti and Sr have not proven to be effective in promoting formation of quasicrystals in cast Al-Mn alloys whilst Fe, Cu, Mg and Si proved to be highly efficient

The influence of the chemical composition and type of alloy on corrosion performances of some medium strength Al-Mg-Si series of alloys

The effect of the chemical composition, i.e. content of silicone (Si) and other alloying elements (Zr, Mn, etc) on the corrosion behaviour and mechanical properties of Al-Mg-Si (6xxx) type alloys was investigated in this paper. Open circuit corrosion potential (OCP) measurements, linear polarization and potentiodynamic anodic/cathodic polarization were employed in order to determine the corrosion behaviour of artificially aged Al-Mg-Si samples in the chloride ions containing aqueous corrosion solutions. The difference in OCPs for the tested 6xxx type alloys in relation to the standard AA1020 alloy was observed to be between 1-4%, except for the AlMg0.65Si0.76Zr0.1 alloy when the difference was 14% (about 100 mV). The presence of zirconium and manganese in AlMgSi0.7 base alloy, that contains small excess of Si, shifts the OCPs to more negative values for -15 mV (~2%) and -88 mV (~11%) in natural water and 0,51 mol NaCl, respectively. All the tested 6xxx type alloys, except AlMg0.7Si1.2Mn0.8, show almost the same corrosion rates and other corrosion characteristics in chloride solution, with mass loss per year between 2.3-3 g/m2

The influence of the chemical composition and type of alloy on corrosion performances of some medium strength Al-Mg-Si series of alloys

The effect of the chemical composition, i.e. content of silicone (Si) and other alloying elements (Zr, Mn, etc) on the corrosion behaviour and mechanical properties of Al-Mg-Si (6xxx) type alloys was investigated in this paper. Open circuit corrosion potential (OCP) measurements, linear polarization and potentiodynamic anodic/cathodic polarization were employed in order to determine the corrosion behaviour of artificially aged Al-Mg-Si samples in the chloride ions containing aqueous corrosion solutions. The difference in OCPs for the tested 6xxx type alloys in relation to the standard AA1020 alloy was observed to be between 1-4%, except for the AlMg0.65Si0.76Zr0.1 alloy when the difference was 14% (about 100 mV). The presence of zirconium and manganese in AlMgSi0.7 base alloy, that contains small excess of Si, shifts the OCPs to more negative values for -15 mV (~2%) and -88 mV (~11%) in natural water and 0,51 mol NaCl, respectively. All the tested 6xxx type alloys, except AlMg0.7Si1.2Mn0.8, show almost the same corrosion rates and other corrosion characteristics in chloride solution, with mass loss per year between 2.3-3 g/m2 . http://dx.doi.org/10.5937/metmateng1402131

Mechanical behavior and corrosion properties of some AA6XXX aluminum alloys in T5 temper

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The Influence of the Chemical Composition on the Corrosion Performances of Some Al-Fe-Si, Al-Mg-Si and Al-Mg-Mn Type of Alloys

Paper presents the results on the corrosion behavior of some Al-Fe-Si, Al-Mg-Si and Al-Mg-Mn alloys in their final commercially usable tempered state. Durability of alloys was quantified and compared in the sense of corrosion rates in aqueous solutions while also having in mind the role of alloy chemistry. Open circuit corrosion potential (OCP) measurements, linear polarization and potentiodynamic anodic/cathodic polarization was employed in order to determine the corrosion behavior of samples in the mixture of chloride ions containing aqueous corrosion ambient. We found out that AlFe0.83Si0.18(AA8079), AlMg0.63Si0.72 (AA6005) and AlMg4Mn (AA5182) alloy exhibited the highest rates of passivation in 0.51 mol NaCl solution. The group of Al-Fe-Si alloys exhibited the greatest sensitivity to the changes in chemical composition under potentiodynamic polarization. Artificially aged Al-Mg-Si extruded profiles and fully annealed (after cold rolling) Al-Mg-Mn sheets exhibit very similar levels of equilibrium potentials E(I=0) in 0.51 mol NaCl solution. In the case of Al-Fe-Si alloys, we found that Fe/Si ratio also plays an important role, next to the total content of Fe and Si. Alloys with high Fe/Si ratios showed almost 30 % lower polarization resistance compared to the alloys with balanced Fe/Si, even in the case of the equal total content of alloying elements. The AlMg0.7Si1.2Mn0.8 alloy aged after quenching in the sprayed water and AlMg4Zn1.3Mn0.4 annealed sheet exhibit very similar levels of corrosion rates in 0.51 mol NaCl solution. http://dx.doi.org/10.5937/metmateng1404217

Microstructure and Mechanical Properties of Hot-Pressed Hydroxyapatite/Poly-I-Lactide Biomaterials

Effects of the hot pressing parameters on the designing of structures and properties of hydroxyapatite/poly-L-lactide (HAp/PLLA) biocomposite blocks have been studied. Interdependences of temperature, pressure and time of hot pressing and the density, compressive strength, elasticity modulus were defined. Microstructures of the fracture surfaces were observed by scanning electron microscopy (SEM). A wide spectrum of block properties such as relative density of 86.2-99.6%, compressive strength of 38.2-139.0 MPa and elasticity modulus of 1.9-10.0 GPa was obtained by varying the hot pressing parameters

Anti-tarnish silver alloys in system ag-cu-zn-si with the addition of aluminum

This paper presents investigations of aluminum addition influence on the corrosion characteristics of the sterling silver Ag-Cu-Zn-Si alloys. The procedure for obtaining Ag-Cu-Zn-Al-Si alloys in small ranges of predefined composition was also presented. Open circuit potential measurements, linear polarization resistance method and potentiodynamic polarization tests were employed to determine corrosion characteristics of the alloys. The materials were tested in a 0.01M sodium sulfide solution. It was shown that the addition of aluminum improves sulfidization resistance and corrosion characteristics. Best results are achieved for the alloy with the following composition 92.5% Ag, 1.9% Cu, 3.7% Zn, 1.6% Al and 0.3% Si

Influence of zinc addition on anti-tarnish silver alloys in four different systems

The presented paper investigates the influence of zinc addition on corrosion characteristics of different sterling silver alloy systems. Open circuit potential measurements, linear polarization resistance method, and potentiodynamic polarization tests were employed to determine the corrosion characteristics of the alloys. The materials were tested in an Artificial Sweat, 0.9% NaCl, and 0.01M Na2S solutions. Based on the presented results, it could be concluded that zinc has the most significant direct impact. The benefits of zinc addition are especially noticeable in aluminum-containing alloy systems, but only up to 3.7 % of Zn. The best results are achieved for alloy AgCu1.9Zn3.7Al1.6Si0.3