Microstructural Evaluation of Semi-Solid and Thixoformed Parts of LM28 Aluminum Alloy

2012 ◽  
Vol 192-193 ◽  
pp. 136-141
Author(s):  
S.G. Shabestari ◽  
P. Ghaemmaghami ◽  
H. Saghafian ◽  
A. Osanlo
Keyword(s):  
Mechanical Properties ◽  
Morphological Changes ◽  
Physical And Mechanical Properties ◽  
Primary Silicon ◽  
Optical Microscope ◽  
Globular Structure ◽  
Cooling Slope ◽  
The Matrix ◽  
Semi Solid ◽  
Cooling Slope Casting

Attractive physical and mechanical properties of aluminum alloys make them very interesting for the automotive industry. The commercial way for manufacturing LM28 alloy is die-casting, but this process encounters several problems such as shrinkage and gas porosities. Their good mechanical properties and high resistance to wear are because of the presence of hard primary silicon particles distributed in the matrix. Therefore, the size and morphology of primary silicon and also the structure of α-Al particles in hypereutectic Al–Si alloys influence the mechanical properties of the alloys. In this research, a new process of manufacturing of this alloy has been developed using LM28 feedstock produced through cooling slope casting. The feedstocks produced via cooling slope casting had a partial globular structure that contained globules, rosettes and dendrites of α-Al. These feedstocks were thixoformed under three different pressures. The primary dendrites and rosettes changed to globular structure. The microstructure of thixoformed parts contained α-Al globules, small primary Si particles dispersed between these globules, and Al-Si eutectic phase. The mechanism of the formation of α-Al globules by this process was explained. Microstructures of as cast specimens, feedstocks produced via cooling slope, specimens that were heat treated in the semi-solid temperature and thixoformed specimens were studied with optical microscope and image analysis. The morphological changes during these processes were interpreted.

Microstructure characterization and evaluation of mechanical properties of stir rheocast AA2024/TiB2 composite

2019 ◽  
Vol 54 (7) ◽  
pp. 981-997
Author(s):  
Semegn Cheneke ◽  
D Benny Karunakar
Keyword(s):  
Mechanical Properties ◽  
Dendritic Structure ◽  
Optical Microscope ◽  
X Ray Diffraction ◽  
Globular Structure ◽  
Cast Sample ◽  
X Ray ◽  
Weight Percentage ◽  
The Matrix ◽  
Fractured Surface

In this research, microstructure and mechanical properties of stir rheocast AA2024/TiB2 metal matrix composite have been investigated. The working temperature was 640℃, which was the selected semisolid temperature that corresponds to 40% of the solid fraction. Two weight percentage, 4 wt%, and 6 wt% of the TiB2 reinforcements were added to the matrix. The field emission scanning electron microscope micrographs of the developed composites showed a uniform distribution of the particles in the case of the 2 wt% and 4 wt% of the reinforcements. However, the particles agglomerated as the weight percentages of the reinforcement increases to 6%. The optical microscope of the liquid cast sample showed the dendritic structure, whereas the rheocast samples showed a globular structure. The X-ray diffraction analysis confirmed the distribution of the reinforcements in the matrix and the formation of some intermetallic compounds. Mechanical properties significantly improved by the addition of the reinforcements in the matrix. An increase in tensile strength of 13.3%, 40%, 28%, and 5% was achieved for the unreinforced rheocast sample, 2 wt%, 4 wt%, and 6 wt% reinforced rheocast samples respectively, compared to the liquid cast sample. An increase in 20% of hardness was attained for the composite with 2 wt% TiB2 compared to the liquid cast sample. According to the fractography analysis, small dimples were observed on the fractured surface of the unreinforced rheocast sample, whereas small and large voids were dominant on the fractured surface of the 2 wt% composite, which shows the ductile fracture mode.

The Elaboration of an Iron Aluminium Alloy and the Study of Impact of the Addition Element on its Physical and Mechanical Properties

2013 ◽  
Vol 686 ◽  
pp. 211-215
Author(s):  
Nadia Metidji ◽  
Nacer Eddine Bacha ◽  
Djamal Saidi ◽  
Slimane Boutarfaia
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Morphological Changes ◽  
Physical And Mechanical Properties ◽  
Antiphase Domain ◽  
Optical Microscope ◽  
Micro Hardness ◽  
X Ray ◽  
B Additions ◽  
Scanning Electron

This work has been undertaken in order to determine the effect of alloying with Ni, Mo and B additions on physical and mechanical properties of FeAl alloys. The structural evolutions and morphological changes alloys were characterized by X. ray diffractometry (XRD), Scanning Electron Microscope (SEM) and an Optical Microscope. Antiphase domain sizes and morphologies are reported and correlations between such ordening phenomena, phase precipitations and mechanical properties (micro hardness at low temperature) are discussed.

Role of SiC ceramic particles on the physical and mechanical properties of Al–4%Cu metal matrix composite fabricated via mechanical alloying

2016 ◽  
Vol 51 (9) ◽  
pp. 1285-1298 ◽  
Author(s):  
Mahnaz Keneshloo ◽  
Moslem Paidar ◽  
Morteza Taheri
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Mechanical Alloying ◽  
Morphological Changes ◽  
Aluminum Matrix ◽  
Diffraction Method ◽  
Physical And Mechanical Properties ◽  
X Ray Diffraction ◽  
Sic Particles ◽  
The Matrix

In the present investigation, Al–Cu composites with SiC particulates were fabricated via mechanical alloying process. The aim of this study was to evaluate the effect of milling time (8, 12, 16 and 32 h), particle size (30 nm and 15 µm) and volume fractions (5, 10 and 15 wt.%) of SiC particles on the metallurgical and mechanical properties. Scanning electron microscopy equipped with X-ray diffraction method was used to investigate the microstructural evolution and morphological changes created during mechanical alloying. Microstructural study indicated that SiC particles were well distributed after the mechanical alloying process. A homogenous distribution of the particles was obtained by 15 wt.% of SiC particles in the aluminum matrix. The results revealed that the SiC particle size also affected the distribution and size of the powders in the matrix and it improved as particle size decreased from 15 µm to 30 nm. The study of mechanical properties clearly showed that a reduction in hardness of composite occurs which is attributed to positive effect of reinforcement particles in resistance to the movement of dislocations. Furthermore, it was found that the wear weight loss of Al–Cu/SiC composite decreases monotonically with increasing SiC content and more uniform particle size distribution. The excellent wear rate was primarily attributed to uniform distribution of the SiC particles.

Physical and Mechanical Properties of Composites with Aluminum Alloy Matrix Designed for Metal Forming

2013 ◽  
Vol 212 ◽  
pp. 59-62 ◽  
Author(s):  
Jerzy Myalski ◽  
Jakub Wieczorek ◽  
Adam Płachta
Keyword(s):  
Mechanical Properties ◽  
Metal Forming ◽  
Matrix Material ◽  
Physical And Mechanical Properties ◽  
Mechanical Mixing ◽  
Alloy Matrix ◽  
Segregation Process ◽  
The Matrix ◽  
Glass Carbon ◽  
Properties Of Composites

The change of matrix and usage of the aluminum alloys designed for the metal forming in making the composite suspension allows to extend the processing possibility of this type of materials. The possibility of the metal forming of the composites obtained by mechanical mixing will extend the range of composite materials usage. Applying of the metal forming e.g. matrix forging, embossing, pressing or rolling, will allow to remove the incoherence of the structure created while casting and removing casting failures. In order to avoid the appearance of the casting failures the homogenization conditions need to be changed. Inserting the particles into the matrix influences on the shortening of the composite solidification. The type of the applied particles influenced the sedimentation process and reinforcement agglomeration in the structure of the composite. Opposite to the composites reinforced with one-phase particles applying the fasess mixture (glassy carbon and silicon carbide) triggered significant limitation in the segregation process while casting solidification. Inserting the particles into the AW-AlCu2SiMn matrix lowers the mechanical properties tension and impact value strength. The most beneficial mechanical properties were gained in case of heterofasess composites reinforced with the particle mixture of SiC and glass carbon. The chemical composition of the matrix material (AW-AlCu2SiMn) allows to increase additionally mechanical characteristics by the precipitation hardening reached through heat casting forming.

METAL COMPOSITE MATERIALS BASED ON TITANIUM ALLOYS, REINFORCED WITH REFRACTORY PARTICLES (review)

2021 ◽  
pp. 36-45
Author(s):  
E.I. Krasnov ◽  
◽  
V.M. Serpova ◽  
L.G. Khodykin ◽  
A.V. Gololobov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Composite Materials ◽  
Literature Review ◽  
Titanium Alloys ◽  
Chemical Nature ◽  
Physical And Mechanical Properties ◽  
Metal Composite ◽  
The Matrix ◽  
Metal Composite Materials

Presents a literature review in the field of methods for strengthening titanium and its alloys by introducing various refractory particles into the matrix. The main problematic issues related to the chemical nature of refractory particles and titanium alloys that arise during hardening are briefly described. The main structural, physical and mechanical properties and morphology of such metal composite materials are described. The dependence of the influence of various refractory particles and their amount, as well as the effect of heat treatment on the physical and mechanical properties of microns based on titanium alloys, is presented.

scholarly journals Physical and Mechanical Properties Evaluation of Particle Board Produced from Saw Dust and Plastic Waste

2018 ◽  
Vol 40 ◽  
pp. 1-8 ◽  
Author(s):  
Atoyebi Olumoyewa Dotun ◽  
Adeolu Adesoji Adediran ◽  
Adisa Cephas Oluwatimilehin
Keyword(s):  
Mechanical Properties ◽  
Physical Properties ◽  
Weight Ratio ◽  
Physical And Mechanical Properties ◽  
Modulus Of Rupture ◽  
Maximum Point ◽  
Mixing Ratios ◽  
Saw Dust ◽  
Three Phase ◽  
The Matrix

The current work reports on the fabrication of composite matrix from saw dust (SD) and recycled polyethylene terephthalate (PET) at different weight ratio by flat-pressed method. Wood plastic composites (WPCs) were made with a thickness of 15 mm after mixing the saw dust and PET followed by a three phase press cycle. Physical properties (Density, Water Absorption (WA) and Thickness Swelling (TS)) and Mechanical properties (Modulus of Elasticity (MOE) and Modulus of Rupture (MOR)) were determined base on the mixing ratios according to the standard. WA and TS were measured after 2 h and 24 h of immersion in water. The results showed that as the density increased, the SD content decreased from 90 % to 50 % into the matrix. However, WA and TS decreases when the PET content increased in the matrix. Remarkably, the MOE and MOR attained a maximum point at 964.199 N/mm2and 9.03 N/mm2respectively in 50 % SD content. In comparism with standard, boards D and E can be classified as medium density boards while A, B and C are low density boards. The results indicated that the fabrication of WPCs from sawdust and PET would technically be feasible for indoor uses in building due to favorable physical properties exhibited. The mechanical properties response showed that it cannot be used for structural or load bearing application.

MICROSTRUCTURAL INVESTIGATION AND MECHANICAL PROPERTIES OF THIXOFORMED AL-6SI-XCU-0.3MG ALLOYS

2017 ◽  
Vol 79 (5-2) ◽  
Author(s):  
Mohd Shukor Salleh ◽  
Nurul Naili Mohamad Ishak ◽  
Saifudin Hafiz Yahaya
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Yield Strength ◽  
Intermetallic Phase ◽  
Dendritic Microstructure ◽  
Microstructural Investigation ◽  
Cu Content ◽  
Cooling Slope ◽  
Cooling Slope Casting

In this study, the effect of different amounts of copper (CU) on the microstructure and mechanical properties of thixoformed Al-6Si-xCu-0.3Mg (x= 3, 4 and 5, mass fraction, %) were investigated. The alloys were prepared via cooling slope casting technique, before there were thixoformed using compression press. All of the alloys were then characterized using optical microscope (OM), scanning electron microscope (SEM) and energy dispersive X-ray (EDX). The results obtained revealed that cooling slope casting produced a non-dendritic microstructure and the intermetallic phase in the thixoformed samples was refined and evenly distributed. The results also revealed that as the Cu content in the alloy increases, the hardness and tensile strength of the thixoformed alloys also increase. The hardness of thixoformed Al-6Si-3Cu was 104.1 HV while the hardness of Al-6Si-5Cu alloy was increased to 118.2 HV. The ultimate tensile strength, yield strength and elongation to fracture of the thixoformed alloy which contained 3wt.% Cu were 241 MPa, 176 MPa and 3.2% respectively. The ultimate tensile strength, yield strength and elongation to fracture of the alloy that contained 6wt.% of Cu were 280 MPa, 238 MPa and 1.2% respectively. The fracture surface of the tensile sample with lower Cu content exhibited dimple rupture while higher Cu content showed a cleavage fracture.

The Influence of the Al-Ti-B/Al-Sr Modification on the Microstructure and Properties of the Hypereutectic Al-Si Alloy in Automotive Piston

2013 ◽  
Vol 744 ◽  
pp. 339-344 ◽  
Author(s):  
Meng Xiang Liu ◽  
Jian Mei Chen
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Friction And Wear ◽  
Eutectic Silicon ◽  
Primary Silicon ◽  
Optical Microscope ◽  
Sr Modification ◽  
Alloy Microstructure ◽  
Compound Modification ◽  
Better Than

By using some types of means such as Optical Microscope (OM), Scanning Electron Microscopy(SEM), the testing of tensile mechanical properties and the testing of friction and wear, the impacts of the Al-5Ti-1B and Al-20Sr modification on the Al-16Si-4Cu-0.5Mg-0.2Mn alloy microstructure, mechanical properties and friction properties are researched. The results turn out that the modification can significantly refine the primary silicon and the eutectic silicon in the alloy, the Al-5Ti-1B mainly refined the primary silicon in the alloy, the Al-20Sr refined the eutectic silicon; the alloy’s effect of refinement after compound modification is better than that in separate metamorphism. Modification can improve the tensile strength and elongation of the alloy: the tensile strength of the alloy has been increased by 65MPa after its compound modification; also the elongation by 0.4%. Modification can improve wear-resisting property of the alloy and also its effect of compound modification is better than that of separate metamorphism. The modification mechanism of Al-5Ti-1B is that Al3Ti and TiB2 belongs to heterogeneous nucleation; while the modification mechanism of Al-20Sr is that the strontium changes the growth pattern of Si phase.

An Experimental Study on Effect of T-Joint’s Root Gap on Welding Properties

2017 ◽  
Vol 863 ◽  
pp. 323-327 ◽  
Author(s):  
Yustiasih Purwaningrum ◽  
Panji Lukman Tirta Kusuma ◽  
Dwi Darmawan
Keyword(s):  
Mechanical Properties ◽  
Base Metal ◽  
Testing Machine ◽  
Low Carbon Steel ◽  
Physical And Mechanical Properties ◽  
Optical Microscope ◽  
Low Carbon ◽  
Weld Metals ◽  
A Value ◽  
Welding Properties

The aimed of this research is to investigate the effect of T-Joint’s root gap on physical and mechanical properties of weld metal. Low carbon steel were joined in T-joint types using MIG (Metal Inert Gas) with variation of root gap. The root gap used were 0 mm, 3 mm and 6 mm. The physical properties examined with chemical composition, microstructure and corrosion using optical microscope. The mechanical properties were measured with respect to the strength and hardness using Universal testing machine and Vickers Microhardness. The results show that the highest value found in welds with a gap of 3 mm with a value of 163.57 MPa. Hardness value is directly proportional to the tensile strength of the material. The highest value found in welds with root gap of 3 mm, followed by root gap of 6 mm, and 0 mm Hardness values in the welding area is higher than the parent metal and HAZ because the number of Si, Mn and Cu elements in the welding metals are bigger than base metal. Weld with all variation of root gap have a good corrosion resistance because the corrosion rate in welds with various root gap have a value below 0.02 mmpy. Microstructure of weld metals were Accicular ferrite, Widmanstatten ferrite, and grain boundary ferrite, while microstructure of base metal and HAZ were ferrite and perlite.

Effect of the Matrix and Reinforcement Sizes on the Microstructure, the Physical and Mechanical Properties of Al-SiC Composites

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
M. A. Salem ◽  
I. G. El-Batanony ◽  
M. Ghanem ◽  
Mohamed Ibrahim Abd ElAal
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Volume Fraction ◽  
Physical And Mechanical Properties ◽  
Particle Sizes ◽  
Matrix Composites ◽  
Volume Fractions ◽  
The Matrix ◽  
Sic Composites ◽  
Sic Particle

Different Al-SiC metal matrix composites (MMCs) with a different matrix, reinforcement sizes, and volume fractions were fabricated using ball milling (BM) and powder metallurgy (PM) techniques. Al and Al-SiC composites with different volume fractions were milled for 120 h. Then, the Al and Al-SiC composites were pressed under 125 MPa and finally sintered at 450 °C. Moreover, microsize and combination between micro and nano sizes Al-SiC samples were prepared by the same way. The effect of the Al matrix, SiC reinforcement sizes and the SiC volume fraction on the microstructure evolution, physical and mechanical properties of the produced composites was investigated. The BM and powder metallurgy techniques followed by sintering produce fully dense Al-SiC composite samples with different matrix and reinforcement sizes. The SiC particle size was observed to have a higher effect on the thermal conductivity, electrical resistivity, and microhardness of the produced composites than that of the SiC volume fraction. The decreasing of the Al and SiC particle sizes and increasing of the SiC volume fraction deteriorate the physical properties. On the other hand, the microhardness was enhanced with the decreasing of the Al, SiC particle sizes and the increasing of the SiC volume fraction.

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