scholarly journals A Study of the Mechanical and Thermal Characteristics of an Al-Si-Fe Alloy Fabricated by Rolling and Heat Treatment

Metals ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 9 ◽  
Author(s):  
Yu Guo ◽  
Ye Wang ◽  
Jieren Yang ◽  
Hongyu Xu ◽  
Maoliang Hu ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermal Properties ◽  
Cast Alloy ◽  
Thermal Characteristics ◽  
Spherical Shape ◽  
Mean Free Path ◽  
Homogeneous Distribution ◽  
Mechanical And Thermal Properties ◽  
Obvious Effect ◽  
T6 Heat Treatment

The effects of a rolling process and heat treatment on the mechanical and thermal properties of an Al-Si-Fe alloy were studied. The achieved thermal conductivity of the as-rolled alloy treated by a T6 heat treatment was 188.22 W/(m·K), which is as good as that of the as-cast alloy treated by the T6 heat treatment directly, mostly because of changes in the silicon morphology. The results also revealed that the lower quantity of precipitated Al8Fe2Si and Mg2Si phases had no obvious effect on the thermal properties of the material because the interphase spaces between precipitated phases were larger than the mean free path of electrons. However, the precipitated second phases influenced the elongation. The best mechanical properties of the Al-Si-Fe alloy were obtained by rolling and T6 treatment. The corresponding best tensile strength, yield strength, and elongation were 244 MPa, 295 MPa, and 9.56%, respectively, which are attributed to the near-spherical shape, small size, homogeneous distribution of the Si particles, and the precipitation strengthening of Mg2Si.

Preparation and Characterization of Micro-Graphite Filled Poly(Lactic Acid) Composites: Part 1 - Rheological and Thermal Properties

2020 ◽  
Vol 981 ◽  
pp. 138-143
Author(s):  
Esa N. Shohih ◽  
Mujtahid Kaavessina ◽  
Henry A. S. Lomi ◽  
Betha P. Pratiwi ◽  
Sperisa Distantina ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Lactic Acid ◽  
Thermal Properties ◽  
Conductive Polymer ◽  
Complex Viscosity ◽  
Poly Lactic Acid ◽  
Homogeneous Distribution ◽  
Mechanical And Thermal Properties ◽  
Blending Method ◽  
Stirring Time

Conductive polymer composites (CPCs) have attracted great attention of researchers due to their enhanced properties such as an adjustable electrical conductivity, good processability, good mechanical and thermal properties, etc. CPCs had many potencies for wider application in electronic devices. Poly (lactic acid) or PLA is one of the interesting polymers used in the developing of these new important materials. PLA properties are comparable to the synthetic petroleum-based polymers such as polyethylene terephthalate (PET), polypropylene (PP), etc. This research focuses on studying the rheological and thermal properties of PLA/micro-graphite as a conductive polymer composite which adjustable its electrical conductivity. In this study, the PLA/micro-graphite was prepared through solvent blending method using chloroform. The micro-graphite composition was varied from 0%, 5%, and 10 % (w/w) with different stirring time (30 and 60 minutes) and then, poured in glass mould. In the melt rheology study, the frequency sweep test showed that the complex viscosity (|η*|) of the bio-composite increased with the micro-graphite loading. The same tendency was also found in thermal property and stability. The melting temperature and thermal degradation were slightly increasing. The crystallinity of PLA was influenced by the presence of micro-graphite. In this solvent blending method, the homogeneous distribution of micro-graphite in the bio-composite required at least 60 minutes (stirred at 650 rpm and 60 °C).

scholarly journals Mechanical and Thermal Properties of Polyurethane Materials and Inflated Insulation Chambers

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1541
Author(s):  
Goran Čubrić ◽  
Ivana Salopek Čubrić ◽  
Dubravko Rogale ◽  
Snježana Firšt Rogale
Keyword(s):  
Mechanical Properties ◽  
Thermal Properties ◽  
Heat Resistance ◽  
Winter Season ◽  
Thermal Characteristics ◽  
Football Players ◽  
Mechanical And Thermal Properties ◽  
Cold Environment ◽  
Target Groups ◽  
Intelligent Clothing

Evaluating mechanical and thermal characteristics of garment systems or their segments is important in an attempt to provide optimal or at least satisfying levels of comfort and safety, especially in the cold environment. The target groups of users may be athletes engaged in typical sports that are trained in the cold, as well as football players that play matches and train outdoors during the winter season. Previous studies indicated an option to substitute the inner layers of an intelligent garment with polyurethane inflated chambers (PIC) to increase and regulate thermal insulation. In this paper, the authors investigate the mechanical properties of polyurethane material with and without ultrasonic joints. Furthermore, they investigate the potential of designed PICs in terms of efficiency and interdependence of air pressure and heat resistance. The results indicated that an inflated PIC with four diagonal ultrasonic joints has the highest ability to maintain the optimal thermal properties of an intelligent clothing system. The influence of direction and number of ultrasonic joints on the mechanical properties of polyurethane material is confirmed, especially in terms of compression resilience and tensile energy.

Effect of Alloying Elements on Mechanical Properties of Al-Si-Cu-Mg Cast Alloys

2015 ◽  
Vol 817 ◽  
pp. 127-131
Author(s):  
Yan Peng Pan ◽  
Zhi Feng Zhang ◽  
Bao Li ◽  
Bi Cheng Yang ◽  
Jun Xu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Performance ◽  
Cast Alloy ◽  
Experimental Results ◽  
Alloying Elements ◽  
Mg Alloy ◽  
T6 Heat Treatment ◽  
Specific Composition ◽  
Cast Alloys

To develop Al-Si cast alloys with high performance is important for lightweighting vehicles. In this study, the effects of the alloying elements such as Si, Cu, Mg contents (5%-7% Si, 1%-3%Cu, 0.3%-0.9%Mg) on mechanical properties of a test Al-Si-Cu-Mg cast alloy was studied to achieve a specific composition. The experimental results show that the Al-6%Si-3%Cu-0.3%Mg alloy has better comprehensive mechanical properties after T6 heat treatment, which indicates a remarkable interaction of the alloying elements for improving performance.

scholarly journals Effect of Ce Addition and Heat Treatment on Microstructure Evolution and Tensile Properties of Industrial A357 Cast Alloy

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1100
Author(s):  
Yanfeng Wang ◽  
Qian Liu ◽  
Zheng Yang ◽  
Changming Qiu ◽  
Kuan Tan
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Rare Earth ◽  
Tensile Properties ◽  
Cast Alloy ◽  
Fracture Pattern ◽  
Unmodified Alloy ◽  
Constitutional Undercooling ◽  
T6 Heat Treatment ◽  
Eutectic Si

The effects of adding different Ce contents (0–0.32 wt.%) on the microstructure, mechanical properties, and fracture morphology of industrial A357 cast alloy in as-cast and T6 heat treatment were studied. The main purpose of this study is to improve the microstructure stability and tensile properties of industrial A357 cast alloy. The microstructural analyses indicate that the addition of Ce causes refinement of the α-Al primary phase for the reason that the formation of intermetallic compounds containing (AlSiCeMg) elements enriches the front of the solid–liquid interface, which causes an increase in constitutional undercooling. Simultaneously, the addition of Ce also affected the characteristics of eutectic Si particles, which make its morphology change from acicular structures into fragmented and spheroidized. This is mainly due to the formation of Ce-rich precipitates during solidification, which increase the constitutional undercooling and suppress the nucleation of the eutectic Si particles, resulting in the change of eutectic Si characteristics. Moreover, the needle-like morphology of a Fe-containing intermetallic is transformed into α(AlSiFeCe) phase containing rare earth Ce when part of the Ce atoms entered β(Al5FeSi) phase compounds. The tensile properties of the modified alloys were improved in the as-cast and T6 heat treatment as a consequence of simultaneous refinement of both secondary dendrite arm spacing and grains and the improvement of eutectic Si particles and Fe-containing intermetallic morphology. The fracture surface of the modified alloy has more dimples than the unmodified alloy, which indicates that the main fracture pattern of the modified alloy is dimple fracture caused by the crack of eutectic Si particles. The optimal percentage of Ce in industrial A357 cast alloy was determined to be 0.16 wt.% according to the change of microstructures structure and mechanical properties. These experimental results provide a new basis for adding rare earth Ce to improve the performance of parts in the actual production of industrial A357 cast alloy.

Investigation of multiple-stresses on mechanical and thermal properties of 9000 h Aged RTV-SiR composites for high-voltage insulation

2020 ◽  
pp. 009524432095358
Author(s):  
Atif Mahmood ◽  
Muhammad Amin ◽  
Hidayatullah Khan ◽  
Israrullah ◽  
Fazal Muhammad ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Thermal Properties ◽  
High Voltage ◽  
Thermal Characteristics ◽  
Superior Performance ◽  
Maximum Deviation ◽  
Mechanical And Thermal Properties ◽  
Multiple Stresses ◽  
Elongation At Break ◽  
Minimum Change

Due to many advantages, polymer composite insulators have been extensively used for high-voltage (HV) transmission lines and substation insulations. The in-service operation, various environmental and electrical stresses degrade their mechanical and thermal characteristics. In this study, nine thousand-hour (9000 h) multi-stress (HV, heat, acid rain, salt fog, ultraviolet (UV) radiation, and humidity) accelerated lab-weathering evaluation of alumina-trihydrate (ATH) and silicon dioxide (SiO2) filled silicone rubber (SiR) composites were utilized. Moreover, to quantify the influence of multiple stresses over 9000 h lab-aging, the tensile strength, elongation at break, hardness, and thermal properties were evaluated and compared with the characterization results of neat (un-aged) composites. Winter and summer-aging cycles were designed in accordance with the actual service environment of Islamabad (Pakistan). Mechanical results of SiR blends showed a decrease in the tensile strength and the elongation at break (EAB), whereas the hardness increased over 9000 h lab-aging. The maximum deviation of ∼57.1% in tensile strength was found for hybrid samples (micro-ATH+ nano-Silica blend: SMNC), whereas the minimum change of ∼25.73% was exhibited by micro-silica-filled SiR specimen SMC3. Compared to neat blends, the maximum variation in EAB was ∼61% for a neat sample (SiR), whereas minimum change was noticed for SMC2 (of ∼31%) over 9000 h lab-aging. Additionally, after 9000 h lab-aging, the maximum (of ∼79.6%) and minimum (of ∼24.4%) variation in hardness was found for hybrid and SiR samples, respectively. Moreover, thermogravimetric (TGA) analysis showed that relative to neat samples, the thermal stability of aged specimens was decreased over weathering. Among aged specimens, only ATH filled samples (SMC1, SMC2) exhibited superior performance for a given temperature range (from 0°C to 900°C) by leaving a higher residual weight of ∼68.6% for SMC2. Hence to simulate and quantify the influence of environmental stresses over insulant performance, accelerated lab weathering can be adopted as an efficient tool.

Phase morphology, mechanical, and thermal properties of fiber-reinforced thermoplastic elastomer: Effects of blend composition and compatibilization

2021 ◽  
pp. 073168442110517
Author(s):  
Ali Fazli ◽  
Denis Rodrigue
Keyword(s):  
Thermal Properties ◽  
Thermoplastic Elastomer ◽  
Interfacial Stress ◽  
Homogeneous Distribution ◽  
Mechanical And Thermal Properties ◽  
Fiber Reinforced ◽  
Crystallinity Degree ◽  
Rubber Phase ◽  
Impact Modification ◽  
The Impact

In this work, recycled high density polyethylene (rHDPE) was compounded with regenerated tire rubber (RR) (35–80 wt.%) and reinforced with recycled tire textile fiber (RTF) (20 wt.%) as a first step. The materials were compounded by melt extrusion, injection molded, and characterized in terms of morphological, mechanical, physical, and thermal properties. Although, replacement of the rubber phase with RTF compensated for tensile/flexural moduli losses of rHDPE/RR/RTF blends because of the more rigid nature of fibers increasing the composites stiffness, the impact strength substantially decreased. So, a new approach is proposed for impact modification by adding a blend of maleic anhydride grafted polyethylene (MAPE)/RR (70/30) into a fiber-reinforced rubberized composite. As in this case, a more homogeneous distribution of the fillers was observed due to better compatibility between MAPE, rHDPE, and RR. The tensile properties were improved as the elongation at break increased up to 173% because of better interfacial adhesion. Impact modification of the resulting thermoplastic elastomer (TPE) composites based on rHDPE/(RR/MAPE)/RTF was successfully performed (improved toughness by 60%) via encapsulation of the rubber phase by MAPE forming a thick/soft interphase decreasing interfacial stress concentration slowing down fracture. Finally, the thermal stability of rubberized fiber-reinforced TPE also revealed the positive effect of MAPE addition on molecular entanglements and strong bonding yielding lower weight loss, while the microstructure and crystallinity degree did not significantly change up to 60 wt.% RR/MAPE (70/30).

Solidification Behavior and Mechanical Properties of Al-Si-Mg Alloy with Ti Addition

2016 ◽  
Vol 850 ◽  
pp. 594-602 ◽  
Author(s):  
Cong Xu ◽  
Cheng Yuan Wang ◽  
Hai Jun Yang ◽  
Zhi Guo Liu ◽  
Hiroshi Yamagata ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Cast Alloy ◽  
Solidification Behavior ◽  
A357 Alloy ◽  
T6 Heat Treatment ◽  
Interdendritic Space ◽  
Cast Alloys ◽  
Ti Addition ◽  
Strength And Ductility

The solidification behavior, microstructural evolution and mechanical properties of Al-Si-Mg foundry alloy with different Ti additions were investigated in the present study. The solidification behavior of those A357 alloys was analyzed through thermal analysis. The microstructures were examined by optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results showed that the addition of Ti could refine grains of A357 as-cast alloy due to a good restriction on the grain growth, but Ti could not refine secondary dendrite arm spacing (SDAS), thus mechanical properties of the A357 as-cast alloy did not improved significantly. After T6 heat treatment, the microstructure with α-Al dendrites with the Al-Si eutectics at interdendritic space was replaced by a homogeneous α-Al matrix with a nonuniform dispersion of discrete, spheroidizing and coarse silicon particles. Hence, compared with the as-cast alloys, both of the strength and ductility of the T6 treated alloys are significantly improved, and an optimal combination of strength and elongation of the A357 alloy can be achieved by the 0.8 wt.% Ti addition after T6 heat treatment.

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