Effect of aging conditions on the mechanical properties and antimicrobial activity of elastomer nanocomposites

2019 ◽  
Vol 39 (4) ◽  
pp. 316-325
Author(s):  
Małgorzata Przybyłek ◽  
Anita Białkowska ◽  
Mohamed Bakar ◽  
Urszula Kosikowska ◽  
Tomasz Szymborski
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperatures ◽  
Inhibitory Effect ◽  
Scanning Electron Microscopy Micrograph ◽  
Uniform Dispersion ◽  
Bactericidal Properties ◽  
Before And After ◽  
Aging Conditions ◽  
Homogeneous Structures ◽  
Antibacterial And Antifungal

AbstractThe present study investigates the effect of thermooxidative and photooxidative aging on the mechanical and bactericidal properties of elastomer nanocomposites (ENs) based on Nanobent ZR2. The mechanical properties and morphologies were analyzed before and after aging. The addition of nanoparticles had a significant effect on the mechanical properties of ENs. Samples containing Nanobent exhibited higher tensile strength before and after aging compared to the reference composition. The addition of nanoparticles attenuated elastomer aging at elevated temperatures and ultraviolet light. Aged nanocomposites showed an inhibitory effect on the growth of bacteria and yeasts. Antibacterial and antifungal activity was only partially reduced after aging using physical methods compared to the activity of probes without aging. Scanning electron microscopy micrograph analysis showed different rough but homogeneous structures, confirming the uniform dispersion of the modified nanoparticles in the elastomer matrix as well as the retention of mechanical properties after the aging process.

Microstructure and Mechanical Properties of Ti-6Al-4V Manufactured by SLM

2015 ◽  
Vol 651-653 ◽  
pp. 677-682 ◽  
Author(s):  
Anatoliy Popovich ◽  
Vadim Sufiiarov ◽  
Evgenii Borisov ◽  
Igor Polozov
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Phase Composition ◽  
Mechanical Behavior ◽  
Ductile Fracture ◽  
Elevated Temperatures ◽  
Initial Material ◽  
Laser Melting ◽  
Microstructure And Mechanical Properties ◽  
Before And After

The article presents results of a study of phase composition and microstructure of initial material and samples obtained by selective laser melting of titanium-based alloy, as well as samples after heat treatment. The effect of heat treatment on microstructure and mechanical properties of specimens was shown. It was studied mechanical behavior of manufactured specimens before and after heat treatment at room and elevated temperatures as well. The heat treatment allows obtaining sufficient mechanical properties of material at room and elevated temperatures such as increase in ductility of material. The fractography of samples showed that they feature ductile fracture with brittle elements.

Studying of Microstructure and Properties of Selective Laser Melted Titanium-Based Alloy

2015 ◽  
Vol 1120-1121 ◽  
pp. 1269-1275
Author(s):  
Anatoly A. Popovich ◽  
Vadim Sh. Sufiiarov ◽  
Igor A. Polozov ◽  
Evgenii V. Borisov ◽  
Maxim Y. Maximov
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Phase Composition ◽  
Mechanical Behavior ◽  
Selective Laser Melting ◽  
Powder Material ◽  
Elevated Temperatures ◽  
Initial Powder ◽  
Laser Melting ◽  
Before And After

The article presents the results of selective laser melting of Ti-6Al-4V alloy. It was studied phase composition and microstructure of the initial powder material, the specimens manufactured by Selective Laser Melting and also the specimens after heat treatment. The effect of heat treatment on microstructure and mechanical properties of the specimens was shown. It was studied the mechanical behavior of the manufactured specimens before and after heat treatment at room and elevated temperatures as well. After heat treatment tests showed that the specimens have decent mechanical properties both at room and elevated temperatures.

Mechanical Properties and Damage Evolution of Siliceous Concrete Subjected to Elevated Temperatures

2016 ◽  
Vol 711 ◽  
pp. 488-495
Author(s):  
Hong Yan Chu ◽  
Jin Yang Jiang ◽  
Wei Sun ◽  
Ming Zhong Zhang
Keyword(s):  
Mechanical Properties ◽  
Damage Evolution ◽  
Nuclear Power ◽  
Elevated Temperatures ◽  
Distribution Model ◽  
Polypropylene Fibers ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Before And After ◽  
Temperature Levels

Siliceous concrete (SC) is applied in European Pressurized Water Reactor that is a key component of the third generation nuclear power plant. This paper investigates the mechanical properties and damage evolution of SC (with and without polypropylene fibers) exposed to high temperatures. The mass loss, compressive strength, splitting tensile strength and spalling sensitivity of SC before and after being heated to 200, 400, 600, 800, and 1000 °C are investigated. The ultrasonic testing technique was used to assess the thermal damage, by evaluating the variations of the ultrasonic wave velocity (UWV) for different temperature levels. According to the available literature, a new relationship between damage and UWV was proposed to establish a damage evolution model of SC. The results indicated that: (a) specimens without polypropylene (PP) fibers suffered severe spalling in the range 380-400°C and 470-510°C, while no spalling took place in the specimens with PP fibers in the whole range 25-1000°C; (b) the damage evolution with and without polypropylene fibers was similar, and could adequately be described by means of a Weibull distribution model.

Effect of Mg Addition on the Mechanical Properties of Rapidly Solidified Al-Mn Alloys at Elevated Temperatures

2010 ◽  
Vol 638-642 ◽  
pp. 339-344
Author(s):  
Makoto Sugamata ◽  
Akio Tomioka ◽  
Yousuke Kubota
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Tensile Strength ◽  
Intermetallic Compounds ◽  
Elevated Temperatures ◽  
Optical Microscope ◽  
Strength Increase ◽  
Positive Effects ◽  
Uniform Dispersion ◽  
Rapidly Solidified

With an aim of clarifying the strength of rapidly solidified P/M materials strengthened by solid solution of Mg and dispersion of transition metal compounds at elevated temperature, Al-2mass%Mn, Al-4mass%Mn and Al-6mass%Mn alloys with varied Mg additions of 0, 1 and 3 mass% were prepared by rapid solidification techniques. Rapidly solidified (RS) flakes were produced by remelting alloy ingots in a graphite crucible, atomizing the alloy melt and subsequent splat-quenching on a rotating water-cooled copper roll under argon atmosphere.　The RS flakes were consolidated to the P/M materials by hot extrusion after vacuum degassing. Cast ingots of these alloys were also hot-extruded under the same conditions to the I/M as reference materials. Metallographic structures and constituent phases were studied for the P/M and I/M materials by optical microscope and X-ray diffraction. Mechanical properties of as-extruded and annealed P/M materials and as-extruded I/M materials were examined by tensile test at room and elevated temperatures under various strain rates. Uniform dispersion of fine intermetallic compounds (Al6Mn) was observed in all the as-extruded P/M materials. Added Mg was present as the solute in I/M and P/M materials alloy even after annealing. The P/M materials containing Mg exhibited higher hardness and strength at room temperature, than those without Mg. It was considered that both solid solution of Mg and dispersion of intermetallic compounds were contributing the hardness and strength increase in the rapidly solidified Al-Mn-Mg alloys. Tensile strength increases with increasing amount of Mg in I/M materials at all testing temperatures. However, strength of as-extruded P/M materials decreases with addition of Mg at 573K and 673K. Thus the positive effects of Mg additions on tensile strength of as-extruded P/M materials disappeared at higher testing temperature. Tensile strength of annealed P/M materials in which dislocation density decreased and compound particle coarsened increased with addition of Mg at elevated temperatures.

Microstructure and Mechanical Properties of Inconel 718 Produced by SLM and Subsequent Heat Treatment

2015 ◽  
Vol 651-653 ◽  
pp. 665-670 ◽  
Author(s):  
Anatoly A. Popovich ◽  
Vadim Sh. Sufiiarov ◽  
Igor A. Polozov ◽  
Evgenii V. Borisov
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Selective Laser Melting ◽  
Inconel 718 ◽  
Elevated Temperatures ◽  
Ductile Failure ◽  
Mechanical Tests ◽  
Laser Melting ◽  
Microstructure And Mechanical Properties ◽  
Before And After

The article presents results of selective laser melting of Inconel 718 superalloy. It was studied phase microstructure of the material obtained by selective laser melting and also the material after heat treatment. The phase composition of the initial powder material, the specimens after selective laser melting before and after heat treatment was studied. The effect of heat treatment on microstructure and mechanical properties of the specimens was shown. It was studied the mechanical behavior of the manufactured specimens before and after heat treatment at room and elevated temperatures as well. The results of impact tests and fractography of the specimens are presented. Mechanical tests showed that the specimens after heat treatment have decent mechanical properties comparable to hot-rolled material. Fractography showed that the obtained material is characterized by ductile failure mode with local elements of brittle fracture.

scholarly journals Thermal resistance of alkaline fused phosphate sludge-based geopolymer mortar

2019 ◽  
Author(s):  
Samira Moukannaa ◽  
Ali Nazari ◽  
Ali Bagheri ◽  
Mohamed Loutou ◽  
Rachid Hakkou
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Thermal Behaviour ◽  
Elevated Temperatures ◽  
Mineralogical Composition ◽  
Optimum Conditions ◽  
Strength Tests ◽  
Before And After ◽  
Different Temperatures ◽  
Fused Phosphate

The present study investigates the thermal behaviour of phosphate sludge-based geopolymers. Phosphate sludge which is a by-product from phosphate beneficiation processes was activated using the alkaline fusion method to improve the geopolymer activity of this material. Then, the mechanical properties as well as the thermal behaviour of the resulted geopolymer mortar were studied. The effect of sodium hydroxide addition and fusion temperature on the mechanical properties and the thermal behaviour of the geopolymers were assessed using compressive strength tests before and after thermal shock cycles at different temperatures (350, 500, 650 °C). The mineralogical composition of the fused materials was investigated using XRD measurement and the microstructure of the geopolymer mortars was studied using FTIR. The obtained results showed that NaOH content as well as the temperature of fusion are essential parameters controlling the structure and the strength of the developed geopolymeric gel. Exposure to elevated temperatures up to 650 °C induces a decrease in compressive strength between 58 and 71%. However, a further increase in the temperature of exposure till 800 °C induces a development of compressive strength. Overall, geopolymers with good compressive strength up to 40 MPa could be synthesized in the optimum conditions of fusion: 10% of NaOH and 550 °C.

MECHANICAL PROPERTIES OF P/M MATERIALS OF RAPIDLY SOLIDIFIED Al-Co-Mg ALLOYS AT ELEVATED TEMPERATURES

2010 ◽  
Vol 24 (06n07) ◽  
pp. 788-796
Author(s):  
MAKOTO SUGAMATA ◽  
OHKI
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperatures ◽  
Hot Extrusion ◽  
Mg Alloys ◽  
Ingot Metallurgy ◽  
Metal Compounds ◽  
Positive Effects ◽  
Uniform Dispersion ◽  
Rapidly Solidified ◽  
Metallurgy Process

With an aim of obtaining aluminum P/M materials strengthened by dispersion of transition metal compounds and solid solution of Mg , Al -2 mass % Co and Al -5 mass % Co alloys with varied Mg additions of 0, 1 and 5 mass% were prepared by rapid solidification techniques. Rapidly solidified flakes were produced by argon gas atomization and subsequent splat quenching on a water-cooled copper roll. The flakes were consolidated to the P/M (Powder metallurgy process is named as P/M) materials by hot extrusion after vacuum degassing. Cast ingots of these alloys were also hot-extruded under the same conditions to the I/M (Ingot metallurgy process is named as I/M) reference materials. Uniform dispersion of fine intermetallic compounds ( Co 2 Al 9) was observed in all the as-extruded P/M materials. Added Mg was present as the solute in the P/M and I/M materials alloy even after annealing at 773K. The P/M materials containing Mg exhibited higher hardness and strength than those without Mg at room temperature. Tensile strength increased with increasing amount of Mg in the I/M materials at elevated temperatures. However, strength of the P/M materials decreased with addition of Mg at 573K and 673K. According to the steady state creep rate and creep rapture time, the creep resistance of the P/M materials containing Mg was clearly inferior to that of Mg -free alloys. Thus the positive effects of Mg additions on mechanical properties of the P/M materials of Al - Co - Mg alloys disappeared at high temperature.

scholarly journals Mechanical Properties of High-Performance Hybrid Fibre-Reinforced Concrete at Elevated Temperatures

2021 ◽  
Vol 13 (23) ◽  
pp. 13392
Author(s):  
Moawiah Mubarak ◽  
Raizal Saifulnaaz Muhammad Rashid ◽  
Mugahed Amran ◽  
Roman Fediuk ◽  
Nikolai Vatin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
High Performance ◽  
Elevated Temperatures ◽  
High Performance Concrete ◽  
Concrete Strength ◽  
Fibre Reinforced Concrete ◽  
Explosive Spalling ◽  
Hybrid Fibre ◽  
Before And After

Deterioration of concrete’s integrity under elevated temperature requires an alteration in its composition to have better thermal stability. Fibre-reinforced concrete has shown significant improvements in concrete strength and this paper aimed to investigate the influence of steel (ST) and polypropylene (PP) fibres on the behaviour of high-performance concrete (HPC) exposed to elevated temperatures. Six mixtures were prepared and cast by adding one or two types of polypropylene fibre (54 and 9 mm) at 0.25 or 0.5% and either singly or in a hybrid combination, along with a fixed volumetric content at 1% of five-dimensional hooked steel (5DH) fibres. At the age of 28 days, samples were heated to the targeted temperature of 800 °C and cooled down naturally to the laboratory temperature. Visual inspection, flexural, split tensile and compressive strengths were examined before and after the exposure to elevated temperatures. Results exhibited that the hybridization of long and short PP fibres, along with the ST fibres, has notably improved all residual mechanical properties of HPC and kept the integrity of concrete after exposure to elevated temperatures. In addition, PP fibres can significantly prevent spalling, but ST fibres were ineffective in mitigating explosive spalling in beams specimens.

Effect of High Temperature Exposure on the Mechanical Properties and Moisture Absorption Kinetics of Graphite/Epoxy Laminates

2006 ◽  
Author(s):  
Levent Aktas ◽  
Nam Hoang Vu ◽  
M. Cengiz Altan
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Elevated Temperatures ◽  
Moisture Absorption ◽  
Slight Reduction ◽  
Absorption Kinetics ◽  
Maximum Increase ◽  
Before And After ◽  
Temperature Exposure ◽  
Kinetics Of

This study investigates the effect of exposure to elevated temperatures on the mechanical properties and moisture absorption kinetics of a graphite/epoxy composite laminate. 16-ply unidirectional AS4/3501-6 laminates are cured in an autoclave. The temperature profile during cure cycle involves a ramp of 5°C/min followed by a 3-hour hold at 177°C (350°F). The test samples obtained from these laminates are subjected to 150, 200, 250, 275, 300 and 325°C for 30min. Flexural strength and stiffness of the samples are characterized by three-point bending tests before and after the temperature exposure. These samples are then immersed into distilled water at 80°C and weighed at regular intervals to characterize their moisture absorption kinetics. Stiffness remained nearly unaffected from exposure to elevated temperatures except for 300 and 325°C. At 300 and 325°C, up to 21% and 58% reductions in flexural stiffness with respect to the control samples is observed, respectively. On the other hand, flexural strength displayed slight reduction at 250°C and resulted in over 60% and 88% deterioration for 300 and 325°C, respectively. Exposure to 150 and 200°C did not result in significant changes in mechanical properties. However, moisture absorption experiments indicated an increase in the rate of diffusion even if the mechanical properties are unaffected. The diffusion coefficient displayed an increase of 27% for 150°C, 75% for 200°C, reaching a maximum increase of 600% for 300°C exposure.

Effect of Aging on Tensile Properties and Microstructures of Eutectic Sn-Pb Solder With Small Amounts of Au and Pd for Aerospace Application

2011 ◽  
Author(s):  
Ryou Kikuchi ◽  
Ikuo Shohji ◽  
Yuta Saitoh ◽  
Norio Nemoto ◽  
Tsuyoshi Nakagawa ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Tensile Properties ◽  
Lead Free ◽  
Microstructural Observation ◽  
Aerospace Application ◽  
Electrode Degradation ◽  
Similar Tendency ◽  
Before And After ◽  
Aging Conditions

In the joint with eutectic Sn-Pb solder and a lead-free Ni/Pd/Au electrode, degradation of mechanical properties of the solder due to dissolution of Au and Pd into the solder would be anxious. In this study, the effect of aging was investigated on tensile properties and microstructures of the eutectic Sn-Pb solder with small amounts of Au and Pd added. In as-cast solders with both Au and Pd added, the tensile strength increases with increasing contents of Au and Pd. A similar tendency was observed after aging at 100°C for 1000 h. The effect of aging on elongation was relatively small and elongation degraded when brittle (Pd,Au)Sn4 phases formed in the solder. In solders with Au ranging from 1 to 5 mass%, regardless of aging conditions investigated, the tensile strength is stable at approximately 50 MPa and 45 MPa before and after aging, respectively. The effect of aging on improvement of elongation was negligible and elongation degraded when rod shaped AuSn4 formed in the solder. On the basis of the result of microstructural observation, it was clarified that the strengthening by dispersion of (Pd,Au)Sn4 phases is superior to softening by microstructure coarsening upon aging when the contents of Au and Pd are 2 mass% and 1 mass% or above, respectively.

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