scholarly journals Evolution of Primary and Eutectic Si Phase and Mechanical Properties of Al2O3/Al-20Si Composites under High Pressure

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 364
Author(s):  
Xiaohong Wang ◽  
ZhiPeng Chen ◽  
Tengfei Ma ◽  
Dongdong Zhu ◽  
Duo Dong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Compressive Strength ◽  
Cleavage Fracture ◽  
Sharp Angle ◽  
Primary Si ◽  
Eutectic Si ◽  
Hot Pressing Sintering ◽  
Solidification Pressure ◽  
Al Matrix

To further improve the mechanical properties of Al-Si alloys. The phase, microstructure and mechanical properties of Al2O3/Al-20Si composites under different pressures were studied. The results show that the phase of Al2O3/Al-20Si composites are composed of α-Al phase, β-Si phase and Al2O3. Under the condition of hot-pressing sintering (0.02 GPa), a large number of Si phases with irregular shape and sharp angle are distributed on the α-Al matrix. Under high pressure solidification, the growth of primary Si phase is inhibited and the eutectic Si is spheroidized obviously. The microhardness of Al2O3/Al-20Si composite increases from 102.5 HV0.05 at 0.02 GPa to 156.4 HV0.05 at 4 GPa, which increases by 52.6%. The compressive strength increased from 381.5 MPa at 0.02 GPa to 469.1 MPa at 4 GPa, increasing by 23%. With the increase of solidification pressure, the fracture mechanism changes from cleavage fracture to quasi cleavage fracture.

scholarly journals Enhancement of the Mechanical Properties in Al–Si–Cu–Fe–Mg Alloys with Various Processing Parameters

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2150 ◽  
Author(s):  
Su-Seong Ahn ◽  
Sharief Pathan ◽  
Jar-Myung Koo ◽  
Chang-Hyun Baeg ◽  
Chan-Uk Jeong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Silicon Content ◽  
Compositional Analysis ◽  
Processing Parameters ◽  
Silicon Phase ◽  
X Ray ◽  
Primary Si ◽  
Transmission Electron ◽  
Eutectic Si

In this research, various processing conditions were implemented to enhance the mechanical properties of Al-Si alloys. The silicon content was varied from hypoeutectic (Si-10 wt.%) to eutectic (Si-12.6 wt.%) and hypereutectic (Si-14 wt.%) for the preparation of Al-XSi-3Cu-0.5Fe-0.6 Mg (X = 10–14%) alloys using die casting. Subsequently, these alloys were hot-extruded with an optimum extrusion ratio (17:1) at 400 °C to match the output extruded bar to the compressor size. An analysis of the microstructural features along with a chemical compositional analysis were carried out using scanning electron microscope along with energy dispersive X-ray spectroscopy and transmission electron microscope. The SEM micrographs of the extruded samples displayed cracks in primary Si, and the intermetallic (β-Al5FeSi) phase was fragmented accordingly. In addition, the silicon phase was homogenously distributed, and the size remained constant. The mechanical properties of the extruded samples were enhanced by the increase of silicon content, and consequently the ductility decreased. By implementing proper T6 heat treatment parameters, coherent Al2Cu phases were formed in the Al matrix, and the Si phase was gradually increased along with the silicon content. Therefore, high tensile strength was achieved, reaching values for the Al-XSi-3Cu-0.5Fe-0.6Mg (X = 10–14%) alloys of 366 MPa, 388 MPa, and 420 MPa, respectively.

scholarly journals Investigation on Microstructures and Mechanical Properties of the Hypoeutectic Al-10Si-0.8Fe-XEr Alloy

Scanning ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Peng Tang ◽  
Yiyuan Liu ◽  
Yanjun Zhao ◽  
Zhiliu Hu ◽  
Huachun Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Secondary Phase ◽  
Metallographic Analysis ◽  
Analysis Techniques ◽  
Microstructure Modification ◽  
Primary Si ◽  
Eutectic Si ◽  
Second Phases ◽  
The Mean

In this paper, the effect of Er addition (0.2, 0.5, 0.65, 0.8, 1.0, and 1.5 wt. %) on the microstructure evolution and tensile properties of as-cast hypereutectic Al-10Si-0.8Fe alloy was investigated. The phases and their morphologies in these alloys were identified by XRD and SEM equipped with EDX with the help of metallographic analysis techniques; the length of the secondary phase (LSP) and secondary dendrite arm spacing (SDAS) of α-Al grain were quantified. The results indicated that the second phases (primary Si, eutectic Si, and iron-rich phases) and α-Al grain were significantly refined when the addition of Er increased from 0 to 0.8 wt. %. The mean LSP and SADS values were decreased to a minimum value when the Er addition reached 0.8 wt. %. However, the second phases and α-Al grain became coarser when the level of Er increased more than 0.8 wt. %. The analysis of XRD shows that Er mainly exists in the form of Er2Si compound. The microstructure modification also has a significant effect on the mechanical properties of the alloy. The yield strength (YS), ultimate tensile strength (UTS), and elongation (EL) increase from 52.86 MPa, 163.84 MPa, and 3.45% to 71.01 MPa, 163.84 MPa, and 5.65%, respectively. From the fracture surface, the promotions of mechanical properties are due to the dispersion and pinning reinforcement caused by the Er2Si phase.

scholarly journals Structural and Mechanical Properties of Amorphous Si3N4 Nanoparticles Reinforced Al Matrix Composites Prepared by Microwave Sintering

Ceramics ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 126-134 ◽  
Author(s):  
Manohar Mattli ◽  
Penchal Matli ◽  
Abdul Shakoor ◽  
Adel Amer Mohamed
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Yield Strength ◽  
Volume Fraction ◽  
Microwave Sintering ◽  
Aluminum Matrix ◽  
Microstructural Investigation ◽  
Porosity Level ◽  
Amorphous Si3n4 ◽  
Al Matrix

The present study focuses on the synthesis and characterization of amorphous silicon nitride (Si3N4) reinforced aluminum matrix nanocomposites through the microwave sintering process. The effect of Si3N4 (0, 1, 2 and 3 wt.%) nanoparticles addition to the microstructure and mechanical properties of the Al-Si3N4 nanocomposites were investigated. The density of Al-Si3N4 nanocomposites increased with increased Si3N4 content, while porosity decreased. X-ray diffraction (XRD) analysis reveals the presence of Si3N4 nanoparticles in Al matrix. Microstructural investigation of the nanocomposites shows the uniform distribution of Si3N4 nanoparticles in the aluminum matrix. Mechanical properties of the composites were found to increase with an increasing volume fraction of amorphous Si3N4 reinforcement particles. Al-Si3N4 nanocomposites exhibits higher hardness, yield strength and enhanced compressive performance than the pure Al matrix. A maximum increase of approximately 72% and 37% in ultimate compressive strength and 0.2% yield strength are achieved. Among the synthesized nanocomposites, Al-3wt.% Si3N4 nanocomposites displayed the maximum hardness (77 ± 2 Hv) and compressive strength (364 ± 2 MPa) with minimum porosity level of 1.1%.

scholarly journals Microstructure and Mechanical Property of Al6Si2Cu Alloy Subjected to Double-Solution Heat Treatment

Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 18
Author(s):  
Seongbin An ◽  
Minsuk Kim ◽  
Chaeeul Huh ◽  
Chungseok Kim
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Aluminum Alloy ◽  
Intermetallic Phase ◽  
Solution Treatment ◽  
Treatment Temperature ◽  
Solution Temperature ◽  
Eutectic Si ◽  
Equilibrium Phases ◽  
Al Matrix

This study aims to develop the mechanical properties of the Al6Si2Cu aluminum alloy through the double-solution treatment. In addition to the Al matrix, large amounts of coarse eutectic Si, Al2Cu intermetallic, and Fe-rich phases were generated through thermo-calc simulation in agreement with the equilibrium phases. The eutectic Si phase is fragmented and spheroidized by the solution treatment as the heat treatment temperature and time increase. The Al2Cu intermetallic phase is dissolved into the Al matrix, resulting in an increase in both strength and elongation. The second-step solution temperature at 525 °C should be an optimum condition for enhancing the mechanical properties of the Al6Si2Cu aluminum alloy.

Microstructure and Tensile Properties of Al-Cu-Si Alloy with Different Solidification Pressures

2009 ◽  
Vol 628-629 ◽  
pp. 593-598
Author(s):  
Xiao Xian Ouyang ◽  
Hai Dong Zhao ◽  
Ke Wu Zhang ◽  
Yuan Yuan Li
Keyword(s):  
Aspect Ratio ◽  
Tensile Properties ◽  
Aging Treatment ◽  
Secondary Dendrite Arm Spacing ◽  
Dendrite Arm Spacing ◽  
Eutectic Si ◽  
Solidification Pressure ◽  
Al Matrix

Microstructure and tensile properties of as-cast and T6-treated Al-4%Cu-3%Si alloy with different applied solidification pressures were investigated. The pressure has significant effect on the formed microstructure. It is observed that as the pressures increase, the porosities were removed, and the size and the secondary dendrite arm spacing of primary α-Al grains decreased evidently, and the morphology of eutectic Si particles changed from long acicular to small granular type. Hence, the tensile properties of the alloy were improved. The research has shown that the aspect ratio (A.R.) of the Si particles decreased after the solution and aging treatment. The A.R of the Si particles in the alloys with applied solidification pressure decreased more remarkably and this indicated that the Si particles can be more prone to be dissolved into α-Al matrix. Thus, the increase of the elongation was achieved.

Effect of Reheating Process on Microstructure and Mechanical Property of A390 Aluminum Alloy

2015 ◽  
Vol 817 ◽  
pp. 173-179 ◽  
Author(s):  
Xue Kong ◽  
Bi Cheng Yang ◽  
Zhi Feng Zhang ◽  
Jun Xu
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Aluminum Alloy ◽  
Evolution Mechanism ◽  
Primary Si ◽  
Maximum Value ◽  
Eutectic Si ◽  
Reheating Process ◽  
The Relationship ◽  
Microstructure And Mechanical Property

The effect of reheating process on the microstructure and mechanical property of A390 aluminum alloy and its evolution mechanism was studied. During reheating process, the microstructure of A390 ingots changed greatly, the microstructure ofα-Al particles changed from dendrite to spherical. As the reheating temperature increased primary Si and eutectic Si gradually grew up and spheroidized while the mechanical properties got the maximum value as the ingot reheating to 540°C. The relationship the between reheating power and microstructure was built. Improving reheating power can restrain the growth of grains, but if the reheating power was too high, the microstructure becomes non-uniform. It has been found that reheating of A390 aluminum alloy experiences two processes of grain combination and Ostwald growing.

scholarly journals Mechanical and Electrical Properties of Nano Al-Matrix Composites Reinforced with SiC and Prepared by Powder Metallurgy

2021 ◽  
Vol 12 (2) ◽  
pp. 2068-2083
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Compressive Strength ◽  
Electron Microscope ◽  
Powder Metallurgy ◽  
Relative Density ◽  
Apparent Porosity ◽  
Matrix Composites ◽  
Al Matrix Composites ◽  
Al Matrix

Nano Al-matrix composites reinforced with SiC were prepared by powder metallurgy process. The percentages of added SiC were varied between 0, 2, 4, 6, and 8 wt. %. The starting powders were milled in high-energy ball mill for 10hrs to convert into nanopowders; then compacted and sintered for 1h in an argon atmosphere at 400, 500, and 570°C. X-ray technique and transmission electron-microscope were utilized to examine the prepared powders, while scanning electron-microscope was utilized to test the sintered composites. The relative density, apparent porosity, electrical conductivity, and mechanical properties (microhardness, elastic moduli, and compressive strength) of sintered composites were studied. The results showed no sign for phase changes after milling, and the SiC reinforcement was uniformly distributed in the matrix. The relative density and electrical conductivity were decreased with increasing SiC content, while the apparent porosity was increased. It is also found that the mechanical properties were improved with increasing SiC content. Also, all properties were improved with increasing sintering temperature. The hardness, compressive strength, bulk modulus of Al-8wt.% SiC composite sintered at 570°C were 885.4 MPa, 276.2 MPa, and 135.9 GPa, respectively.

scholarly journals The Effect of SiO2 Content and Shape on Mechanical Properties of Al Matrix Composites

2021 ◽  
Author(s):  
Davoud Khademi ◽  
Elahe Khodeir ◽  
Seyed Mostafa Mahdizadeh ◽  
Hamideh Yari
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Compressive Strength ◽  
Weight Percent ◽  
Processing Parameters ◽  
Ammonium Bromide ◽  
Moderate Increase ◽  
Matrix Composites ◽  
Al Matrix Composites ◽  
Al Matrix

Abstract Physical properties and processing parameters of the reinforcing phase such as shape and content can dramatically influence the mechanical properties of the composites. In this project, the effect of different shapes of silicon dioxide or silica (SiO2) reinforcement including nanoparticle and nanotube as well as their weight percent (1, 3, 5 and 10 wt %) on the mechanical properties of aluminum (Al) composite were investigated. The silica nanotubes (SNTs) were prepared by hydrothermal methods. In order to achieve a good dispersion, Al powders were coated by cetyl trimethyl ammonium bromide (CTAB) to obtain a surface positive charge. Then, SiO2–Al powders were obtained by electrostatic self-assembly to realize the homogeneous adsorption of SiO2 nano reinforcement on Al powders. Finally, SiO2-reinforced Al matrix composites were fabricated by powder metallurgy. Characterization of composites was carried out by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). For determination of the mechanical properties of the composite, the compressive strength and density were investigated.Results showed a significant reduction in the relative density from 98% to 84% for composites containing 0 to 10 wt % of SiO2. The compressive strength exhibited a moderate increase by adding SNTs while in samples containing SiO2 nanoparticles, the mechanical properties improved and reached a peak value of 225 MPa at 5 wt % SiO2 nanoparticles (~40% increase compared to pure Al). However, a further increase in nanotubes content resulted in a considerable reduction in compressive strength. This can be attributed to the increase in porosity and agglomeration of nano reinforcement in the composite.

Microstructure of gas-atomized Al-20 wt. % Si-1 wt. % Ni powders studied by electron microscopy

1994 ◽  
Vol 9 (10) ◽  
pp. 2519-2523 ◽  
Author(s):  
Byong-Taek Lee ◽  
Byong-Sun Chun ◽  
Kenji Hiraga
Keyword(s):  
Electron Microscopy ◽  
Crystallographic Relationship ◽  
Primary Si ◽  
Eutectic Si ◽  
Relationship Of ◽  
Al Matrix

The microstructure of gas-atomized Al-20 wt. % Si-1 wt. % Ni powders was investigated by electron microscopy. Primary Si crystals about 2 μm in size are homogeneously distributed in the Al matrix. Eutectic Si crystals about 50 nm in size are precipitated with the definite crystallographic relationship of 〈110〉Si ‖ 〈110〉Al. Most of the interfaces between Al and Si are semicoherently bonded with close-packed planes of {111}Si and {111}Al. The special crystallographic relationship and interfaces are interpreted by matching between Si and Al lattice spacings.

Effect of Solid Solution under High Pressure on the Microstructures and Mechanical Properties of AM60B Alloy

2011 ◽  
Vol 130-134 ◽  
pp. 3216-3220
Author(s):  
Qiu Xiang Liu ◽  
Rui Jun Zhang ◽  
Miao Zhang
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Grain Size ◽  
High Pressure ◽  
Compressive Strength ◽  
Ambient Pressure ◽  
Aging Treatment ◽  
Crystal Grains ◽  
Microstructures And Mechanical Properties ◽  
Strength And Plasticity

Effect of solid solution under high pressure on the microstructures and mechanical properties of AM60B alloy has been investigated. The results show that solid solution under high pressure leads to refined crystal grains of α-Mg phase in the alloys after aging treatment. When the solid solution pressure is about 4GPa, the smallest grain size can be obtained, which is only 8.4% of the grain size when the solid solution is carried out under ambient pressure. Moreover, hardness and compressive strength of AM60B after aging treatment both increase remarkably when the solid solution is performed under high pressure. The superior compressive strength and plasticity can be achieved at 5GPa.

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