Papers by Keyword: Al-Based Alloy

Abstract: The present research describes the comparison of numerical and physical simulation of hot high strain rate torsion tests for Al-based alloys in order to clarify the accuracy of calculations using basic grades of materials in Deform-3D^TM software. A comparative visual analysis of the results is presented. Obtained data on the distribution of temperatures, strains, stresses and strain rates during the torsion test are discussed.

Abstract: In order to develop new protective materials for magnesium alloy, Al-based alloys with different Si-content were fabricated by copper mold casting. Microstructure, erosion properties of the ingot samples were characterized or tested by using spectrum analysis, optical imcroscope, salt testing machine etc, respectively. The results indicated that the microstructure of Al-1.9Si-1.32Mg-0.40Mn was mostly dendritic crystal. That of Al-13Si consisted of α-Al, flaky eutectic silicon and primary crystal silicon. That of Al-18Si-0.01%P was consistent of a large proporation of primary crystal silicon phase, a part of eutectic silicon phase and a little of α-Al phase. With Si-content increasing, anti-corrosion properties of Al-based alloy gradually improved, which could provide theoretical principle to determine chemical elements of protective materials for magnesium alloy.

Abstract: To develop high wear-resistant protective materials for magnesium alloy, high-silica Al-based alloy modified via P-element was fabricated by DC casting method. Microstructure of ingot samples was observed by using optical microscopy (OM), etc. The results demonstrated that Al-Si-0.01%P alloy with unique microstructure and without defects such as voids and rarefaction might be generated by processing control. Owing to modification by Al-P interalloy, primary crystal silicon phase in hypereutectic Al-Si alloy were refined effectively. Its size in Al-18Si-0.01%P alloy decreased from 50μm to 20μm, and distributed uniquely than that in Al-18Si alloy. Al-P acted as heterogeneous core of primary crystal silicon phase, which was the main mechanism for Al-P interalloy to modify primary crystal silicon in Al-Si alloy.

Abstract: This paper presents an analysis of an advanced squeeze casting process suitable for the manufacturing of high performance industrial components more quickly and cheaply. After a short description of the process, some produced components are considered. The components, in A380 alloys, have been T6 heat treated and their soundness has been certified by non destructive tests. All considered components have been designed for advanced application in the automotive field, in particular for quite important sport cars. Standard samples for tensile and impact tests have been machined directly from the previous components. After the execution of the tests the fracture surface of samples has been observed by SEM in order to analyze details and to evaluate the influence of the process and of the alloy on the fracture behavior. On polished transverse sections of samples the microstructure of the alloy has been observed, highlighting a mainly globular shaped microstructure as expression of the attained semi-solid conditions during the processes. A critical analysis has been developed to evaluate the real potential and to present some criticism of the process.

Abstract: In a flow forming process of automobile wheels of Al-based alloys, plastic deformation of the rim part is performed by rollers from the periphery side, while the inner periphery is fixed on a steel mandrel and is slightly deformed. Therefore, the rim part has a strain-graded microstructure in the thickness direction. In this study, the effects of the strain-graded plastic deformation on mechanical properties of an Al-Si cast alloy have been investigated. The strain-graded plastic deformation in this study was done by hot rolling of an Al alloy plate together with a steel plate. The two plates were joined at one end in the longitudinal direction and were rolled from the joined edge at 330 oC using a roller with a roll diameter of 200 mm and a rotation speed of 66 per minute. The chemical composition of the alloy was Al-7mass%Si-0.3mass%Mg-0.3mass%Fe. The rolled Al alloy plate had a strain-graded microstructure in the thickness direction; the strain was the highest at the roller side surface and the lowest at the steel plate side surface. The rolling also brought about a Si particle size graded microstructure. The eutectic Si rods were broken by the rolling deformation and the Si particle size was the smallest at the roller side surface and the largest at the steel plate side surface. On the other hand, a normal rolling deformation of the Al alloy plate without the steel plate was also performed for comparison. The rolled sample having the strain-graded and Si particle size graded microstructure exhibited much　more excellent bending strength and ductility compared with the normally rolled sample.

Abstract: X-ray tools are being powerful methods for qualitative and quantitative analyses of nanocrystalline materials This work is an overview of detailed X-ray investigations relative to microstructural studies applied for a refined binary Al-based alloys thin films system as samples deposited on glass substrates. Energy dispersive analysis of X-ray (EDAX), X-ray diffraction (XRD) and transmission electron microscopy (TEM) methods were used to determine the chemical composition, the microstructure parameters and the solubility of copper in aluminum.

Abstract: The mechanical alloying processes was employed to fabricate Al-4at.%Zr alloy with nano-sized grains and very fine Al3Zr compounds. The phase transformations and the stability of the phases formed during mechanical alloying and heat treatment processes were investigated. The grain sizes of the alloys immediately after milling and following the subsequent heat treatment at 550°C were 54.2nm and 106.4nm, respectively. Some of Zr atoms were dissolved into the Al matrix and most of them reacted with hydrogen produced by decomposition of PCA(process control agent) to form ZrH2 during mechanical alloying process. These ZrH2 hydrides decomposed gradually after the heat treatment. Stable Al3Zr with a DO23 structure was formed by heat treatment at temperature of more than 4500C. The hardness of the Al-4at.%Zr alloy was more than two times higher than those of other Al-based alloys.

Abstract: Al-La-Ni-Fe alloys of three different compositions (Al82La10Ni4Fe4, Al85La9Ni3Fe3 and Al88La6Ni3Fe3) were prepared high-energy milling in a planetary ball-mill (AGO-2). Complete amorphization was observed for the Al82La10Ni4Fe4 alloy after milling for 350 h at a rotational speed of 300 rpm. In contrast, the Al85La9Ni3Fe3 and Al88La6Ni3Fe3 powders contained the FCC Al phase even for prolonged milling. The amorphization tendency was found to increase in the order of Al88La6Ni3Fe3 < Al85La9Ni3Fe3 < Al82La10Ni4Fe4, which may well be ascribed to the increasing atomic size mismatch of the constituent elements on La addition. DSC analyses of amorphous samples revealed two-stage crystallization processes for all three alloys, however, with strong variations in the thermal stability upon compositional changes. As observed by SEM, amorphous powders consisted of particles with nearly spherical shape and diameters ranging from 5 to 20 µm.

Abstract: The kinetics of liquid Ga penetration along grain boundaries in pure Al, Al-Mn (50 ppm Mn) and Al-Ga alloys (with concentration 0.7, 1 and 3% mass. Ga) was studied. It was shown that crack-like channels filled by liquid Ga were formed along all grain boundaries. Their width was about 1-3 µm. Investigation of quenched state showed that in all samples, channels had grown with linear kinetics, and that the propagation rate depended on impurity concentration in alloys: 35µm/s for Al-Mn alloy, 14 µm/s for pure Al and 9±1 µm/s for Al with (0.7-3) % Ga alloys. The difference in penetration rates of pure Al and Al based alloys are discussed in terms of internal stress and mechanical properties.