Modelling of the Effects of Entrainment Defects on Mechanical Properties in a Cast Al-Si-Mg Alloy

2013 ◽  
Vol 765 ◽  
pp. 225-229 ◽  
Author(s):  
Yang Yue ◽  
William D. Griffiths ◽  
Nick R. Green
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Mechanical Strength ◽  
Aluminium Alloy ◽  
Defect Concentration ◽  
Mg Alloy ◽  
Filling Process ◽  
Double Oxide ◽  
Mould Filling ◽  
Alloy Castings

Entrainment defects such as double oxide films and entrapped bubbles occur frequently in aluminium alloy castings during the mould-filling process, and are very detrimental to both mechanical properties, and reproducibility of casting properties. In this study a modelling algorithm was used to predict the formation and distribution of entrainment defects in Al-Si-Mg alloy castings. The tensile strength of cast test bars was compared with either the number of defects, or the defect concentration within the bars obtained from the simulation. A general relationship between the mechanical strength of the cast test bars and the quantity of estimated defects was apparent.

Optically Transparent Polymethyl Methacrylate Composites made with Glass Fibers of Varying Refractive Index

1997 ◽  
Vol 12 (4) ◽  
pp. 1091-1101 ◽  
Author(s):  
Seunggu Kang ◽  
Hongy Lin ◽  
Delbert E. Day ◽  
James O. Stoffer
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Refractive Index ◽  
Mechanical Strength ◽  
Glass Fiber ◽  
Polymethyl Methacrylate ◽  
Optical Transmission ◽  
Annealing Temperature ◽  
Glass Fibers ◽  
Optically Transparent

The dependence of the optical and mechanical properties of optically transparent polymethyl methacrylate (PMMA) composites on the annealing temperature of BK10 glass fibers was investigated. Annealing was used to modify the refractive index (R.I.) of the glass fiber so that it would more closely match that of PMMA. Annealing increased the refractive index of the fibers and narrowed the distribution of refractive index of the fibers, but lowered their mechanical strength so the mechanical properties of composites reinforced with annealed fibers were not as good as for composites containing as-pulled (chilled) glass fibers. The refractive index of as-pulled 17.1 μm diameter fibers (R.I. = 1.4907) increased to 1.4918 and 1.4948 after annealing at 350 °C to 500 °C for 1 h or 0.5 h, respectively. The refractive index of glass fibers annealed at 400 °C/1 h best matched that of PMMA at 589.3 nm and 25 °C, so the composite reinforced with those fibers had the highest optical transmission. Because annealed glass fibers had a more uniform refractive index than unannealed fibers, the composites made with annealed fibers had a higher optical transmission. The mechanical strength of annealed fiber/PMMA composites decreased as the fiber annealing temperature increased. A composite containing fibers annealed at 450 °C/1 h had a tensile strength 26% lower than that of a composite made with as-pulled fibers, but 73% higher than that for unreinforced PMMA. This decrease was avoided by treating annealed fibers with HF. Composites made with annealed and HF (10 vol. %)-treated (for 30 s) glass fibers had a tensile strength (∼200 MPa) equivalent to that of the composites made with as-pulled fibers. However, as the treatment time in HF increased, the tensile strength of the composites decreased because of a significant reduction in diameter of the glass fiber which reduced the volume percent fiber in the composite.

Preparation Techniques and Property Evaluations of Highly Air Permeable Needle-Punched Geotextiles

2015 ◽  
Vol 749 ◽  
pp. 278-281
Author(s):  
Jia Horng Lin ◽  
Jing Chzi Hsieh ◽  
Jin Mao Chen ◽  
Wen Hao Hsing ◽  
Hsueh Jen Tan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Service Life ◽  
Mechanical Strength ◽  
Pore Structure ◽  
Test Results ◽  
Needle Punching ◽  
Pet Fibers ◽  
Environmental Requirements ◽  
Preparation Techniques

Geotextiles are made of polymers, and their conjunction with different processes and materials can provide geotextiles with desirable characteristics and functions, such as filtration, separation, and drainage, and thereby meets the environmental requirements. Chemical resistant and mechanical strong polymers, including polyester (PET) and polypropylene (PP), are thus used to prolong the service life of the products made by such materials. This study proposes highly air permeable geotextiles that are made with different thicknesses and various needle punching speeds, and the influences of these two variables over the pore structure and mechanical properties are then examined. PET fibers, PP fibers, and recycled Kevlar fibers are blended, followed by being needle punched with differing spaces and speeds to form geotextiles with various thicknesses and porosities. The textiles are then evaluated for their mechanical strength and porosity. The test results show that a thickness of 4.5 cm and 1.5 cm demonstrate an influence on the tensile strength of the geotextiles, which is ascribed to the webs that are incompletely needle punched. However, the excessive needle punching speed corresponding to a thickness of 0.2 cm results in a decrease in tensile strength, but there is also an increase in the porosity of the geotextiles.

The Effect of Scandium on the Mechanical Properties of A356 Aluminium Alloy

2016 ◽  
Vol 707 ◽  
pp. 144-147
Author(s):  
Ying Pio Lim ◽  
Wei Hong Yeo ◽  
A. Masita
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aluminium Alloy ◽  
Die Casting ◽  
A356 Alloy ◽  
Charpy Impact ◽  
Casting Process ◽  
Die Casting Process ◽  
Charpy Impact Strength ◽  
A356 Aluminium Alloy

In this project, the addition of scandium (Sc) into A356 aluminium alloy was studied for its effect on the mechanical properties after gravity die casting process. Scandium addition was administered at the weight percentages of 0.1, 0.2 and 0.3. The results obtained in this work revealed that scandium can significantly enhance the mechanical properties of A356 alloy in terms of tensile strength, hardness and charpy impact strength. In general, the addition of 0.2 wt% Sc in A356 alloy was found to be able to achieve the maximum tensile strength of 172.94MPa as compared to 136.03MPa for sample without Sc. No significant improvement in tensile strength was found when more than 0.3wt% added to the alloy. As for hardness, the sample with 0.3 wt% Sc attained the maximum Vicker’s hardness of 86.60 HV as compared to 76.48 HV for unmodified A356. Similarly, the addition of 0.3wt% Sc in A356 can achieve highest impact energy of 2.71J as compare to 1.09J for unmodified A356.

Effects of Casting Geometry on the Mechanical Properties of A201 Aluminum Alloy Castings in Chromite Sand Molds

2015 ◽  
Vol 1104 ◽  
pp. 149-153
Author(s):  
Yeong Sant Kuo
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Systematic Change ◽  
Alloy Plate ◽  
Proper Design ◽  
Aluminum Alloy Plate ◽  
Alloy Castings

Systematic change of riser size together with variation of thickness and length of A201 aluminum alloy plate castings were studied to investigate the correlation between mechanical properties and porosity content. The molds with end chill for plate castings were made of 100% chromite sand by CO2 process. If soundness throughout the whole plate casting has to be guaranteed, the riser diameter should be proper design to the dimension of the plate. The tensile strength and elongation of A201 aluminum alloy plate casting is governed by riser diameter, thickness, and length of the plate.

scholarly journals Effect of magnesium on some mechanical properties of 1200 Aluminium alloy

2021 ◽  
Vol 23 (2) ◽  
pp. 147-152
Author(s):  
M. D. Shittu ◽  
A. E. Olaniyi ◽  
A. A. Daniyan ◽  
D. A Isadare ◽  
K. M. Oluwasegun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Impact Strength ◽  
Aluminium Alloy ◽  
Magnesium Content ◽  
Mechanical Tests ◽  
Dispersion Hardening ◽  
Dispersion Strengthening ◽  
Hardening Material ◽  
Commercial Aluminium

This paper investigated the effect of magnesium as a dispersion strengthening material on some mechanical properties of 1200-Aluminium (Al-Fe-Si) alloy, a typical commercial aluminium alloy used in the production of household utensils. 1200-Aluminium (Al-Fe-Si) alloy containing varying percentages of the dispersion hardening material (i.e. Magnesium) were produced and mechanical tests namely; hardness, tensile strength and impact strength were carried out. Also, the microstructures of the cast materials were studied. The results showed that increase in magnesium content, as dispersion hardening material improved the hardness, tensile strength and caused a slight decrease in impact strength of the 1200-Aluminium alloy. It is inferred from this work that using magnesium as a dispersion hardening material brings about corresponding improvement in some mechanical properties of 1200-Aluminium (Al-Fe-Si) alloy. Keywords: Magnesium, Aluminium alloy, dispersion strengthened, reinforced alloy, crystallographic formation Depth, Geothermal Energy

scholarly journals Comparison of Multilayer Transparent Wood and Single Layer Transparent Wood With the Same Thickness

2021 ◽  
Vol 8 ◽  
Author(s):  
Yan Wu ◽  
Yajing Wang ◽  
Feng Yang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Mechanical Strength ◽  
Light Transmission ◽  
Single Layer ◽  
Attenuated Total Reflection ◽  
Raw Material ◽  
Light Transmittance ◽  
Sodium Chlorite ◽  
Water Contact

In this paper, poplar was used as raw material, sodium chlorite was used to delignify it in acidic environment, and then epoxy resin was vacuum impregnated in the delignified wood template to prepare transparent wood. Moreover, in order to imitate the lamination method of plywood, the multilayer transparent wood was prepared by means of staggered vertical lamination. The purpose of this paper is to study the physical and chemical properties of multilayer transparent wood, and to explore the application potential of multilayer transparent wood as a new material by comparing with single layer transparent wood with the same thickness. The weight of wood components in the transparent wood prepared in this experiment accounts for about 30–45% of the weight of composite materials. Scanning electron microscopy (SEM) measurements, Fourier transform attenuated total reflection infrared spectroscopy (ATR-FTIR) characterization, weight gain measurements, UV transmittance measurements, color difference measurements, water contact angle measurements and mechanical properties measurements were used to study. The results showed that as the thickness of the transparent wood increased, the cracks between the resin and the wood cell wall increased, and the interface showed an uneven state. In the case of the same thickness, the multilayer transparent wood was made by laminating transparent wood sheets, with fewer internal cracks and smooth interfaces. Its light transmittance is better than single layer transparent wood. Moreover, compared with single layer transparent wood with the same thickness, the lightness of multilayer transparent wood decreased, and tended to yellow and red. Due to the removal of lignin, the tensile strength of transparent wood decreased during the preparation process. However, it can be seen from the mechanical strength test that the tensile strength of multilayer transparent wood is much higher than that of single layer transparent wood. To a certain extent, multilayer transparent wood can improve the mechanical strength of transparent wood. To conclude, multilayer transparent wood is a kind of natural transparent material with large thickness, good light transmission and excellent mechanical properties, and it has a good development prospect.

scholarly journals Correlations and Scalability of Mechanical Properties on the Micro, Meso and Macro Scale of Precipitation-Hardenable Aluminium Alloy EN AW-6082

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 608
Author(s):  
Anastasiya Toenjes ◽  
Heike Sonnenberg ◽  
Axel von Hehl
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Aluminium Alloy ◽  
Aluminium Alloys ◽  
Volume Fraction ◽  
Solution Annealing ◽  
Macro Scale ◽  
Testing Cost ◽  
Physical Correlations

The mechanical properties of heat-treatable aluminium alloys are improved and adjusted by three different heat treatment steps, which include solution annealing, quenching, and aging. Due to metal-physical correlations, variations in heat treatment temperatures and times lead to different microstructural conditions with differences in the size and number of phases and their volume fraction in the microstructure. In this work, the investigations of the correlation between microhardness measurements on micro samples and the conventional mechanical properties (hardness, yield strength and tensile strength) of macro samples and the comparability of the different heat treatment states of micro and macro samples made of a hardenable aluminium alloy EN AW-6082 will be discussed. Using the correlations between the mechanical properties of micro samples and macro samples, the size of the samples and, thus, the testing cost and effort can be reduced.

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