Microstructure, microhardness, tensile, electrical, and thermal properties of the Al-Mn-xSi ternary alloys (original) (raw)
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International Journal of Cast Metals Research, 2017
In this work, effect of alloying elements (X = Cu, Co, Ni, Sb and Bi) and growth rates on the microstructure, physical properties (electrical resistivity, enthalpy and specific heat) of the directionally solidified Al-Si eutectic alloy have been investigated. Al-12.6Si-2X (wt. %) samples were prepared using metals of 99.99% high purity in the vacuum atmosphere. These alloys were directionally solidified under constant temperature gradient, G (7.80 K/mm) and different growth rates, V (8.3-166.0 μm/s). Flake spacing (λ) and electrical resistivity (ρ) were measured from the solidified samples. The variation of electrical resistivity with temperature in the range of 300-500 K for alloying elements in the Al-Si eutectic cast alloy was also measured. The enthalpy of fusion (ΔH) and specific heat (C p) for the same alloy were determined by a differential scanning calorimeter from the heating curve during the transformation from solid to liquid.
2017
In this study, influences of growth velocity and composition (Fe content) on the microstructure (rod spacing) and mechanical properties (microhardness, ultimate tensile strength and fracture surface) of Al–Mn–Fe ternary alloys have been investigated. Al–1.9 Mn–xFe (x=0.5, 1.5 and 5 wt. %) were prepared using metals of 99.99% high purity in the vacuum atmosphere. At a constant temperature gradient (6.7 K/mm), these alloys were directionally solidified upwards under various growth velocities (8.3–978 μm/s) using a Bridgman-type directional solidification furnace. The results show that two kinds of Al-rich α-Al phase and Fe-rich intermetallic (Al
Microstructure, Mechanical, Electrical and Thermal Properties of the Al-Si-Ni Ternary Alloy
Zenodo (CERN European Organization for Nuclear Research), 2015
In recent years, the use of the aluminum based alloys in the industry and technology are increasing. Alloying elements in aluminum have further been improving the strength and stiffness properties that provide superior compared to other metals. In this study, investigation of physical properties (microstructure, microhardness, tensile strength, electrical conductivity and thermal properties) in the Al-12.6wt.%Si-%2wt.Ni ternary alloy were investigated. Al-Si-Ni alloy was prepared in vacuum atmosphere. The samples were directionally solidified upwards with different growth rate V (8.3− − − −165.45 µm/s) at constant temperature gradient G (7.73 K/mm). The flake spacings (λ), microhardness (HV), ultimate tensile strength (σ), electrical resistivity (ρ) and thermal properties (∆H, C p , T m) of the samples were measured. Influence of the growth rate and spacings on microhardness, ultimate tensile strength and electrical resistivity were investigated and relationships between them were obtained. According to results, λ values decrease with increasing V, but HV, σ and ρ values increase with increasing V. Variations of electrical resistivity (ρ) of solidified samples were also measured. The enthalpy of fusion (∆H) and specific heat (C p) for the alloy was also determined by differential scanning calorimeter (DSC) from heating trace during the transformation from liquid to solid. The results in this work were compared with the previous similar experimental results.
Journal of Alloys and Compounds, 2017
In this research, effect of alloying elements (X=Cu, Co, Ni, Sb and Bi) and growth rates on the microstructure and mechanical properties (microhardness and tensile strength) of the directionally solidified Al-Si eutectic alloy have been investigated. Al-12.6Si-2X (wt. %) samples were prepared using metals of 99.99% high purity in the vacuum atmosphere. These alloys were directionally solidified under constant temperature gradient and different growth rates (8.3-166.0 µm/s) by using a Bridgman-type growth apparatus. Interflake spacings, microhardness and tensile strength were expressed as functions of growth rate. The effects of alloying elements and growth rates on microstructure, microhardness and tensile strength were determined. According to experimental results, the microstructures, microhardness and tensile strength of the solidified Al-SiX samples changes with alloying elements (Cu, Co, Ni, Sb and Bi) and the growth rates. The results obtained in this work have been compared with the similar experimental research in the literature.
Physical Properties of Directionally Solidified Al-1.9Mn-5Fe Alloy
Journal of Materials Engineering and Performance, 2020
Al-1.9Mn-5Fe (wt.%) alloy was prepared by adding 5 wt.% Fe to the eutectic Al-Mn alloy. This alloy undergone controlled solidification under four different growth velocities (V) in Bridgman-type furnace. Eutectic spacings (k), microhardness (HV), ultimate tensile strength (r U) and electrical resistivity (q) of these alloys were determined. While the HV and r U increased with increasing V values or decreasing k, the elongation (d) values decreased. In addition, relationships between these parameters were investigated using linear regression analysis. Microstructure photographs of directionally solidified samples were taken by optical microscope and scanning electron microscope (SEM). The eutectic spacings were measured from these photographs. The relationships among growth velocity (V), eutectic spacing (k), microhardness (HV), ultimate tensile strength (r U) and electrical resistivity (q) were measured by suitable method and tests. The q measurements were carried out depending on V and temperature (T). While temperature coefficient of resistivity (a TCR) was calculated from the q-T curve, the values of thermal conductivity (K) predicted by Wiedemann-Franz (W-F) and Smith-Palmer (S-P) equations. It was found that the microstructure, microhardness, tensile strength and electrical resistivity were affected by both eutectic spacing and the growth velocity.
Materials Research
Metals solidification involves the transformation of the molten metal back into the solid state. Solidification structures impact heavily on the final product's characteristics. The microstructure effects on metallic alloys properties have been highlighted in various studies and particularly the dendrite arm spacing influence upon the mechanical properties such as tensile strength has been reported. In the present investigation, Al-10wt%Si-2wt%Cu and Al-10wt%Si-5wt%Cu alloys were directionally solidified upward under transient heat flow conditions. The experimental results include solidification thermal parameters such as tip growth rate and cooling rate, optical microscopy, volume fraction of the eutectic mixture, primary dendritic arm spacing and ultimate tensile strength. Experimental growth laws of primary dendrite arm spacing as a function of the solidification thermal parameters are proposed. The Hall-Petch mathematical expressions were used to correlate the ultimate tensile strength as a function of the primary dendritic arm spacing. It was found that the alloy with higher copper content had a more refined structure. More refined structures had higher ultimate tensile strength values.
Journal of Materials Engineering and Performance, 2003
An alloy of composition Al-12.6 wt.% Si was prepared using metals of 99.99% purity. Weighed amounts of aluminium and silicon were melted in the vacuum-melting furnace. This irregular eutectic alloys were directionally solidified upward with a constant growth rate V (8.3 × 10 −3 mm/s) and different temperature gradients G (2.0-7.8 K/mm) and also with a constant temperature gradient G (7.8 K/mm) and different growth rates V (8.3-498.7 × 10 −3 mm/s) in the directional solidification furnace. The interflake spacings and microhardness H V were measured from both transverse section and longitudinal section of the specimen. The variations of H V with respect to G, V, and have been determined by using the linear regression analysis method. It has been shown that H V increases with the increasing values of G and V. On the other hand H V values decreases with the increasing values. The Hall-Petch type relationships obtained in this work have been compared with the previous works.
Measurements of Microstructural, Mechanical, Electrical, and Thermal Properties of an Al–Ni Alloy
International Journal of Thermophysics, 2013
The Al-7.5 wt% Ni alloy was directionally solidified upwards with different temperature gradients, G (0.86 K • mm −1 to 4.24 K • mm −1) at a constant growth rate, V (8.34 µm • s −1). The dependence of dendritic microstructures such as the primary dendrite arm spacing (λ 1), the secondary dendrite arm spacing (λ 2), the dendrite tip radius (R), and the mushy zone depth (d) on the temperature gradient were analyzed. The dendritic microstructures in this study were also compared with current theoretical models, and similar previous experimental results. Measurements of the microhardness (HV) and electrical resistivity (ρ) of the directionally solidified samples were carried out. Variations of the electrical resistivity (ρ) with temperature (T) were also measured by using a standard dc four-point probe technique. And also, the dependence of the microhardness and electrical resistivity on the temperature gradient was analyzed. According to these results, it has been found that the values of HV and ρ increase with increasing values of G. But, the values of HV and ρ decrease with increasing values of dendritic microstructures (λ 1 , λ 2 , R, and d). It has been also found that, on increasing the values of temperature, the values of ρ increase. The enthalpy of fusion (H) for the Al-7.5 wt%Ni alloy was determined by a differential scanning calorimeter from a heating trace during the transformation from solid to liquid.
Rem: Revista Escola de Minas, 2014
Al-Sn alloys are widely used in tribological applications. In this study, thermal, microstructural and microhardness (HV) analysis were carried out with an Al-5.5wt.%Sn alloy ingot produced by horizontal directional transient solidification. The main parameters analyzed include the growth rate (V L) and cooling rate (T R).These thermal parameters play a key role in the microstructural formation. The dendritic microstructure has been characterized by primary dendritic arm spacing (λ1) which was experimentally determined and correlated with V L, and T R. The behavior presented by the Al-5.5wt.%Sn alloy during solidification was similar to that of other aluminum alloys, i.e., the dendritic network became coarser with decreasing cooling rates, indicating that the immiscibility between aluminum and tin does not have a significant effect on the relationship between primary dendritic arm spacing and the cooling rate. The dependence of the microhardness on V L, T R and λ1 was also analyzed....
Journal of Alloys and Compounds, 2015
Transient unidirectional solidification experiments have been carried out with an Al-3 wt%Mg-1 wt%Si alloy under cooling rates ( _ T) in the range 0.2-45 K/s. A reverse cells > dendrites transition is shown to occur with the high-cooling rate cellular region associated with _ T > 2 K/s and the dendritic region with _ T < 0.8 K/s. Experimental growth laws correlating the cellular and dendritic spacings with the cooling rate are proposed. It is shown that the microhardness is directly influenced by both morphologies of the Al-rich matrix and by the relative fractions of Mg 2 Si and Fe bearing intermetallics that vary differently with the cooling rate.