scholarly journals Evolution of Microstructure and Mechanical Properties of LM25–HEA Composite Processed through Stir Casting with a Bottom Pouring System

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 230
Author(s):  
Mekala Chinababu ◽  
Nandivelegu Naga Krishna ◽  
Katakam Sivaprasad ◽  
Konda Gokuldoss Prashanth ◽  
Eluri Bhaskara Rao

Aluminum matrix composites reinforced by CoCrFeMnNi high entropy alloy (HEA) particulates were fabricated using the stir casting process. The as-cast specimens were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and transmission electron microscopy (TEM). The results indicated that flake-like silicon particles and HEA particles were distributed uniformly in the aluminum matrix. TEM micrographs revealed the presence of both the matrix and reinforcement phases, and no intermetallic phases were formed at the interface of the matrix and reinforcement phases. The mechanical properties of hardness and tensile strength increased with an increase in the HEA content. The Al 6063–5 wt.% HEA composite had a ultimate tensile strength (UTS) of approximately 197 MPa with a reasonable ductility (around 4.05%). The LM25–5 wt.% HEA composite had a UTS of approximately 195 Mpa. However, the percent elongation decreased to roughly 3.80%. When the reinforcement content increased to 10 wt.% in the LM25 composite, the UTS reached 210 MPpa, and the elongation was confined to roughly 3.40%. The fracture morphology changed from dimple structures to cleavage planes on the fracture surface with HEA weight percentage enhancement. The LM25 alloy reinforced with HEA particles showed enhanced mechanical strength without a significant loss of ductility; this composite may find application in marine and ship building industries.

2015 ◽  
Vol 1101 ◽  
pp. 89-92
Author(s):  
K.V. Sreenivas Rao ◽  
S. Sanman

The remarkable high tensile strength and very high aspect ratio of carbon nanotubes make them valuable components for mechanically reinforced composite materials. In this study, Carbon Nanotube (CNT) reinforced aluminum matrix composites were prepared by simple stir casting route with different percentages of Carbon Nanotube reinforcement. The prepared nanocomposite specimens were subjected to evaluation of mechanical properties and microstructure. It was evident from the study that, as the weight fraction of nanotube in the matrix increases, the ultimate tensile strength, macro and micro-hardness also increases. The microstructures show clustering of the carbon nanotubes in the matrix. The difficulties experienced in uniform dispersion of Carbon Nanotube in the matrix to achieve optimum desired properties are discussed.


2020 ◽  
Vol 17 (36) ◽  
pp. 47-57
Author(s):  
Hammar Ilham AKBAR ◽  
Eko SUROJO ◽  
Dody ARIAWAN ◽  
Aditya Rio PRABOWO

Lightweight materials with low-cost production have been developed in recent years. The addition of ceramics and oxide particles such as Al2O3, SiC, and SiO2 has been improving in the mechanical properties of aluminum matrix composites (AMCs). As a solution, the use of natural reinforcing material continues to investigate. This paper investigates sea sand as an alternative reinforcement to AMCs. The Al 6061 was used as the matrix and sea sand as reinforcement. The manufacturing of the composite was conducted by stir casting route with variation 0, 2, 4, 6 %wt of the reinforcement. The composite was tested in hardness and tensile strength, the hardness test was obtained according to ASTM E-10, and the tensile test was conducted according to JIS Z2201 standard. Composite density decreases linearly with the addition of the reinforcement from 2 %wt to 6%wt, and the same phenomenon is obtained in porosity, the porosity increases with the addition of sea sand particles from 2%wt to 6%wt. The decline in density due to the lower density of sea sand particles compared to the aluminum matrix. Higher the sea sand particle that disperses into the matrix resulted in a lower density of the composite. Increasing porosity caused a higher fraction of reinforcement resulting in wider surface contact between matrix and reinforcement that promote the porosity. The hardness and ultimate tensile strength of AMCs increase with increasing of sea sand particles content. The presence of an oxide compound on the sea sand increased the mechanical properties of the composite. Increasing in mechanical properties indicate the sea sand particle dispersed into the matrix and sea sand can be used as engineering purpose material.


2019 ◽  
Vol 25 (4) ◽  
pp. 253 ◽  
Author(s):  
Manoj Kumar Pal ◽  
Arnav Vikram ◽  
Vineet Bajaj

<p class="AMSmaintext">Aluminium6061 alloy composites containing various volume fractions of Silicon Carbide (SiC) particles (0, 5%, 10%, 15%, 20% and 25%) were prepared by stir casting method. In the current study,<strong> </strong>microstructures and mechanical properties of cast silicon carbide (SiC) reinforced aluminum matrix composites (AMCs) were investigated. Optical microscopic examination, SEM, tensile strength test, hardness test and elongation test were carried out. The results showed that with the addition of SiC reinforcements in Aluminum6061 matrix increased hardness and tensile strength however, decreased elongation at 25% SiC reinforced AMC. Hardness and tensile strength were observed to be are maximum at 25% SiC and elongation is minimum at 25% SiC. Microstructural observation confirmed clustering and homogeneous distribution of SiC particles in the Al6061 matrix.</p>


2020 ◽  
Vol 988 ◽  
pp. 17-22
Author(s):  
Suryana ◽  
Indah Uswatun Hasanah ◽  
Muhammad Fikri Fadhillah ◽  
Yordan Valentino Putra

The effects of graphite and magnesium (Mg) addition on mechanical properties and microstructure of aluminum matrix composites (AMCs) have been investigated in this work. Aluminum alloy (ADC-12) was combined with graphite and Mg produced by stir casting. The effect of addition of graphite into the matrix has been studied with variation 2, 4 and 6 wt-% for each composite. The addition of Mg as wetting agent was introduced wit 0.4, 0.6 and 0.8 wt-% to promote wettability between ADC-12 and graphite. All composites were characterized both microstructures analysis and mechanical properties include tensile strength and hardness. The higher reinforcement content, the higher porosity formed, due to the tendency of de-wetting as well as particles agglomeration. One of the main intermetallic phase present evenly in aluminum matrix is Mg2Si. The addition of magnesium in the material that will form Mg2Si primary phases which have a high hardness value of these composites.


2013 ◽  
Vol 592-593 ◽  
pp. 614-617 ◽  
Author(s):  
Konstantinos Anthymidis ◽  
Kostas David ◽  
Pavlos Agrianidis ◽  
Afroditi Trakali

It is well known that the addition of ceramic phases in an alloy e.g. aluminum, in form of fibers or particles influences its mechanical properties. This leads to a new generation of materials, which are called metal matrix composites (MMCs). They have found a lot of application during the last twenty-five years due to their low density, high strength and toughness, good fatigue and wear resistance. Aluminum matrix composites reinforced by ceramic particles are well known for their good thermophysical and mechanical properties. As a result, during the last years, there has been a considerable interest in using aluminum metal matrix composites in the automobile industry. Automobile industry use aluminum alloy matrix composites reinforced with SiC or Al2O3 particles for the production of pistons, brake rotors, calipers and liners. However, no reference could be cited in the international literature concerning aluminum reinforced with TiB particles and Fe and Cr, although these composites are very promising for improving the mechanical properties of this metal without significantly alter its corrosion behavior. Several processing techniques have been developed for the production of reinforced aluminum alloys. This paper is concerned with the study of TiB, Fe and Cr reinforced aluminum produced by the stir-casting method.


2021 ◽  
Vol 871 ◽  
pp. 3-8
Author(s):  
Rui Zhi Jian ◽  
Shang Cheng Zhou ◽  
Yun Fei Xue

To improve the mechanical properties of a sintered WHA using high entropy alloy as the matrix (W-HEA), investigations were carried out to apply deformation strengthening method of hot swaging on the W-HEA. The W-HEA samples were swaged around 1300°C with the 10%, 15% and 20% of reduction in area. The results show that the strength and hardness of the W-HEA composite increased with the increasing degree of deformation. And the aspect ratio of tungsten grains increases along the axial direction in the swaged alloys. The hardness of W-HEA with a 20% reduction in area reaches 448 HV, and the dynamic compression yield strength is about 1911 MPa. After hot swaging, the hardness and strength of the W-HEA are greatly improved compared with the sintered W-HEA.


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