scholarly journals Influence of the Small Sc and Zr Additions on the As-Cast Microstructure of Al–Mg–Si Alloys with Excess Silicon

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1797
Author(s):  
Evgenii Aryshenskii ◽  
Maksim Lapshov ◽  
Jurgen Hirsch ◽  
Sergey Konovalov ◽  
Viacheslav Bazhenov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Phase Composition ◽  
Software Package ◽  
Complete Dissolution ◽  
Thermo Calc Software ◽  
Lower Temperature ◽  
Cast Condition ◽  
L12 Structure ◽  
Cast Microstructure

This research is devoted to the study effects of complex alloying of Al-0.3 wt.% Mg-1 wt.% Si and Al-0.5 wt.% Mg-1.3 wt.% Si alloys by small additions of Sc and Zr on the microstructure in the as-cast condition. The effect of small additions of these elements on the microhardness, electrical conductivity, grain size and phase composition of the indicated alloy systems was studied. The methods of optical and electron microscopy were used for the study. Moreover, the phase composition was calculated using the Thermo-Calc software package. The study showed a strong effect of the chemical composition of investigated alloys on the size of the grains, which, with a certain combination of additives, can decrease several times. Grain refinement occurs both due to supercooling and formation of primary Al3Sc particles in the liquid phase. Alloys based on Al-0.5 wt.% Mg-1.3 wt.% Si are more prone to the formation of this phase since a lower concentration of Sc is required for it to occur. In addition, more silicon interacts with other elements. At the same time, Al-0.3 wt.% Mg-1 wt.% Si requires lower temperature for complete dissolution of Mg2Si, which can contribute to more efficient heat treatment, which includes reducing the number of steps. TEM data show that during ingot cooling (AlSi)3ScZr dispersoid precipitates. This dispersoid could precipitate as coherent and semi-coherent particles with L12 structure as well as needle-shaped particles. The precipitation of coherent and semi-coherent particles during cooling of the ingot indicates that they can be obtained during subsequent multistage heat treatment. In addition, in the Al0,5Mg1,3Si0,3Sc alloy, metastable β’’ (Mg5Si6) are precipitated.

Effect of Heat Treatment on Phase Composition and Microstructure of Al-Cu-Fe Alloys with Quasicrystalline Phases

2014 ◽  
Vol 794-796 ◽  
pp. 833-838
Author(s):  
Marina Samoshina ◽  
Pavel Bryantsev
Keyword(s):  
Heat Treatment ◽  
Phase Composition ◽  
Quasicrystalline Phase ◽  
Cast State ◽  
Equilibrium Conditions ◽  
Crystalline Phases ◽  
Different Temperatures ◽  
Fe Alloys ◽  
Cast Condition

The microstructure and phase composition of alloys Al-Cu-Fe in as-cast state and after heat treatment at different temperatures were investigated. The presence of a quasicrystalline phase Al65Cu20Fe15 which coexists with crystalline phases in as-cast condition is found. The formation of single quasicrystalline phase composition in Al - 40 wt.% Cu - 17 wt.% Fe alloy after annealing at 800 °C for 100 hours is established. After heat treatment, i.e. closer to equilibrium conditions, the quasicrystalline phase Al65Cu20Fe15 is transformed into quasicrystalline phase Al13Cu4Fe3 with more complicated lattice.

scholarly journals CHARACTERIZATION OF THE SOL-GEL PROCESS IN THE SYSTEM YxBax+nCu2x+nOδ (x = 1, n=1, x=2, n=3, x=3, n=2)

2017 ◽  
pp. 31-34
Author(s):  
A. Pilipenko ◽  
I. Fesych ◽  
S. Nedilko ◽  
A. Dzyazko
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Solid Phase ◽  
Sol Gel ◽  
Complex Oxide ◽  
Present Calculation ◽  
Calculation Algorithm ◽  
Oxide Systems ◽  
Chemical Homogeneity ◽  
Lower Temperature

With the help of sol-gel technology was obtained superconducting compound number YxBax+nCu2x+nOδ (x=1, n=1; x=2, n=3; x=3, n=2) with submicron size particles. As a gel maker in these systems was used citric acid monohydrate. An extensive scheme fusion technology was shown. The process described synthesis using thermal, infrared spectroscopic analysis and scanning electron microscopy. There are some aggregations of microparticles mostly for the phases that are synthesized at higher temperatures. Due to Thermal Analysis of modes were optimized heat treatment samples. According to IR spectroscopy were controlled processes of decomposition of the charge and the formation of the superconducting phase. It was grounded the choice of analysis methods for the starting compounds and the present calculation algorithm for this synthesis. Studies have shown that even at the beginning of the synthesis batch contained no impurity compound allowing argued that the sol-gel synthesis is a promising method that provides high homogeneity of the material the early stages of the synthesis and enables lower temperature and a subsequent heat treatment. The results of electron microscopy showed that due to the relatively low temperature of synthesis occurs the formation of submicron sized particles, while solid-phase techniques facilitate rapid crystal growth due to the formation of liquid phases at high temperature. The principles and ideas described in this paper can be adapted to more complex oxide systems. Thus, in this paper describes how you can achieve chemical homogeneity at the molecular level in multicomponent systems YxBax+nCu2x+nOδ (x=1, n=1; x=2, n=3; x=3, n=2) using sol-gel technology.

Structure and Phase Composition of Biomedical Alloys of the Ti – Nb System in Cast Condition and After Heat Treatment

2019 ◽  
Vol 60 (9-10) ◽  
pp. 659-665 ◽  
Author(s):  
A. Thoemmes ◽  
I. V. Ivanov ◽  
A. A. Ruktuev ◽  
D. V. Lazurenko ◽  
I. A. Bataev
Keyword(s):  
Heat Treatment ◽  
Phase Composition ◽  
Cast Condition

Synthesis of nanocomposite coating of electrodeposed amorphic layers of the Ni–P–W system

2020 ◽  
pp. 53-60
Author(s):  
A. V. Krasikov
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Differential Scanning Calorimetry ◽  
Phase Composition ◽  
Diffraction Analysis ◽  
Nanocomposite Coating ◽  
Nanocrystalline Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray

The processes of the formation of the nanocomposite coating of Ni–11.5% P–5%W were studied during the heat treatment of amorphous electrodeposited layers. Using the method of differential scanning calorimetry, the temperature of the onset of crystallization of the nanocrystalline phase Ni3P was determined. X-ray diffraction analysis showed that heat treatment produces Ni3P phosphides and, presumably, Ni5P2, the size of which, according to electron microscopy, is 5–50 nm. The influence of the duration of heat treatment on the phase composition and microhardness of coatings is investigated.

Influence of Si Content on Tensile Properties and Fractography of Al–Mg–Si Ternary Alloys

2021 ◽  
Vol 21 (3) ◽  
pp. 2005-2009
Author(s):  
Shah Abdul Wahid ◽  
Seong-Ho Ha ◽  
Bong-Hwan Kim ◽  
Young-Ok Yoon ◽  
Hyun-Kyu Lim ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Scanning Electron Microscopy ◽  
Yield Strength ◽  
Tensile Properties ◽  
Ternary Alloys ◽  
Si Content ◽  
Cast Condition ◽  
Iron Bearing ◽  
Scanning Electron

This study investigated the heat treatment response and tensile properties of Al–6 mass%Mg–xSi (x = 1, 3, 5, and 7 mass%) ternary alloys. Further, the fracture behavior of these alloys in response to heat treatment for different temper conditions was also examined. Scanning electron microscopy–energy dispersive X-ray spectrometry (SEM–EDS) analysis of the as-cast alloys revealed, in all of them, the presence of iron-bearing phases (in a size range of 10˜60 μm) that did not dissolve or become refined upon heat treatment. Additionally, eutectic Mg2Si and Al3Mg2 phases were found in Alloy I (Al–6Mg–1Si), while eutectic Mg2Si and Si phases were found in the rest of the alloys. In the as-cast condition, the tensile properties of the examined alloys decreased in relation to increasing Si content. Nonetheless, after heat treatment, the yield strength of the alloys with high Si content (>3 mass%) increased significantly compared with that in the as-cast condition. A yield strength greater than 300 MPa was achieved in both Alloy III (Al–6Mg–5Si) and Alloy IV (Al–6Mg–7Si), although this was achieved at the expense of ductility. According to the fractography of the tensile-fractured surfaces undertaken using optical and scanning electron microscopy, fractures of the iron-bearing phases were found to be the source of cracking in alloys with high Si content. In the case of those with low Si content (≤3 mass%), cracks were believed to have been caused by the debonding of iron-bearing phases from the aluminum matrix.

Effect of Mineralizers on MnNb2O6 Powder Prepared by Hydrothermal Method

2010 ◽  
Vol 156-157 ◽  
pp. 1010-1013
Author(s):  
Yong Ping Pu ◽  
Yong Yong Zhuang ◽  
Kai Chen ◽  
Ning Xu
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Phase Composition ◽  
Hydrothermal Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Highly Dispersed ◽  
Scanning Electron

Pure MnNb2O6 powders was successfully prepared by hydrothermal method using Nb2O5•nH2O and Mn(NO3)2 as precursors and HCl, HF, NaOH, NH4OH solutions as mineralization agent. The phase composition and morphology of the prepared powder were characterized by X-ray diffraction and scanning electron microscopy. The effect of mineralizers on phase formation was investigated. The results show that the MnNb2O6 powders with crystallite size of ~24nm can be obtained with Mn(NO3)2 and Nb2O5•nH2O as precursors in neutral and alkaline solution at 200 for 168h. The particle size of the MnNb2O6 powder was ~300nm after heat treatment at a temperature of 600 . The SEM photographs show that the morphology of the MnNb2O6 powder are rod-like particles and the MnNb2O6 powders are highly dispersed.

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.

scholarly journals Microstructure and Properties of a Novel Al-Mg-Si Alloy AA 6086

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 368
Author(s):  
Franc Zupanič ◽  
Matej Steinacher ◽  
Sandi Žist ◽  
Tonica Bončina
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Thermal Analysis ◽  
Transmission Electron Microscopy ◽  
Tensile Testing ◽  
Energy Dispersive Spectrometry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Cast Condition

In this work, we investigated a novel Al-Mg-Si alloy, which was developed from an AA 6082, in order to considerably improve the yield and tensile strengths whilst retain excellent ductility. The new alloy possesses a higher content of Si than specified by AA 6082, and, in addition, it contains copper and zirconium. The alloy was characterized in the as-cast condition, after homogenization, extrusion, and T6 heat treatment using light microscopy, scanning and transmission electron microscopy with energy dispersive spectrometry, X-ray diffraction, differential thermal analysis and tensile testing. After T6 temper, tensile strengths were around 490 MPa with more than 10% elongation at fracture. The microstructure consisted of small-grained Al-rich matrix with α-AlMnSi and Al3Zr dispersoids, and Q′-AlCuMgSi and β-Mg2Si-type precipitates.

Processing and Characterization of Al2Ti/Al 3Ti Two-Phase Alloys

1998 ◽  
Vol 552 ◽  
Author(s):  
M. J. Lukitsch ◽  
J. E. Benci
Keyword(s):  
Heat Treatment ◽  
Solution Heat Treatment ◽  
Hot Forging ◽  
Al Alloy ◽  
Two Phase ◽  
Al Content ◽  
Material Condition ◽  
Material Conditions ◽  
Lower Temperature ◽  
Cast Condition

ABSTRACTSeveral buttons of each of three binary Ti-Al alloys containing nominally 70, 71 and 72 at.% Al were prepared from elemental Ti and Al by plasma arc-melting. One button of each composition was then either solution heat-treated, subjected to a two-step heat treatment, or hot forged. Each composition and material condition was then characterized using SEM/EDS and microhardness testing. The results show that while all three compositions have a predominantly two-phase, coarse microstructure in the as-cast condition, it is possible to produce an essentially single phase material through an appropriate solution heat treatment for the two lower Al content alloys. A fine two-phase microstructure can be achieved through an additional, lower temperature heat treatment step. The microhardness results show that the solution heat treatment reduced the hardness for all three compositions compared to the as-cast condition while hot forging as-cast samples increased hardness. The 70% Al alloy has the highest hardness for all four material conditions studied while the 71% Al alloy has the lowest hardness in three of the four material conditions.

Microstructural Phenomena Occurring during Early Stages of Cavitation Erosion of Al-Si Aluminium Casting Alloys

2015 ◽  
Vol 227 ◽  
pp. 255-258 ◽  
Author(s):  
Bartłomiej Dybowski ◽  
Mirosław Szala ◽  
Andrzej Kiełbus ◽  
Tadeusz Hejwowski
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Scanning Electron Microscopy ◽  
Cavitation Erosion ◽  
Precipitation Hardening ◽  
Aluminium Casting ◽  
Casting Alloys ◽  
Cast Condition ◽  
Scanning Electron ◽  
Erosion Parameter

The researches have concerned cavitation erosion of AlSi7Mg and AlSi11Mg aluminium casting alloys. The alloys have been investigated in the as-cast condition and after the precipitation hardening. The cavitation erosion tests were performed using vibratory cavitation erosion equipment in 5 minutes. Resistance to cavitation of tested materials was estimated by means of MDE (mean depth of erosion) parameter according to ASTM G32. After the cavitation tests eroded surface of the specimens has been observed by means of scanning electron microscopy. The roughness of the surface was measured on profile contact tester. The best resistance for cavitation erosion exhibited AlSi7Mg alloy after heat treatment, the weakest AlSi11Mg alloy in as-cast condition.

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