Wyniki wyszukiwania - BazTech

1

Badania wpływu minerałów hunterytu/hydromagnezytu oraz kalcytu pod kątem niepalności i właściwości mechanicznych kompozytów drzewnych

Atay Gül Yilmaz, Loboichenko Valentyna, Wilk-Jakubowski Jacek Łukasz

Cement Wapno Beton

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2024

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R. 29, nr 1

40--53

PL

W pracy zbadano właściwości dodatków mineralnych w kompozytach drzewnych, które wpływają na palność materiału, a jednocześnie są przyjazne dla środowiska. W artykule poddano analizie wyniki pomiarów kompozytów drewnianych, będących naturalnym materiałem budowlanym wielu domów, a także elementów ich wyposażenia. Jako matrycę zastosowano trociny drzewne. W pracy zbadano wpływ współobecności kalcytu i minerału mieszanego huntyt/hydromagnezyt. Kalcyt zastosowano jako minerał pomocniczy oprócz huntytu/hydromagnezytu, w celu uzyskania lepszego środka zmniejszającego palność zgodnie z normą UL94 i właściwości mechanicznych kompozytu drzewnego, takich jak wytrzymałość na zginanie i moduł sprężystości przy zginaniu. Uzyskane wyniki oceniano w zależności od zawartości składników mineralnych w kompozytach. Wyniki wykazały, że próbka 40S/50H/10C jest optymalna pod względem stosunku modułu sprężystości do niepalności. Materiały ognioodporne można stosować w budownictwie, a także w elektrotechnice, np. w gaśnicach akustycznych [np. do budowy falowodu].

EN

This work examines the characteristics of mineral additives in wood composites that affect the fire retardant properties of the material, and at the same time are environmentally friendly. The paper analyzes the results of measurements for wood composites, which is the natural building material of many houses, as well as elements of their furnishings. Sawdust waste was applied as a matrix. In the paper, a co-presence effect of calcite and huntite/hydromagnesite mineral was investigated. The calcite mineral was used as auxiliary minerals in addition to the huntite/hydromagnesite mineral to obtain a better flame retardant according to the UL94 standard and mechanical properties in the wood composite, such as flexural strength and flexural modulus. The results obtained were measured and evaluated depending on the mineral content of the composites. The results indicated that sample 40S/50H/10C is the most optimal in terms of the ratio of the modulus of flexibility and fire retardant characteristics. Fire retardant materials can be used in the construction industry, as well as in the electrical engineering applications, such as for acoustic fire extinguishers [e.g. for waveguide construction].

2

Mechanical properties and energy of sandstone under cyclic loading in evolutionary pattern experimental studies

Xu Daqiang, Zhang Peisen, Yan Wei, Zhang Xiaole, Dong Yuhang, Niu Hui

Archives of Mining Sciences

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2023

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Vol. 68, no. 2

351--370

EN

In order to explore the mining failure law of deep coal seam floor and clarify the mechanical behavior and energy change in the floor strata during mining, the mechanical properties and energy evolution law of sandstone under cyclic loading with different confining pressures (20, 30, 40 MPa) were studied using the Rock Top multi-field coupling tester. The results are as follows: (1) the hysteresis phenomenon of a rock stress-strain curve under cyclic loading is evident. Moreover, the hysteresis loop migrates to the direction of strain increase, and the fatigue damage caused by cyclic loading has a certain weakening effect on the peak strength of rock; (2) both the number of cycles and the axial strain show a nonlinear change characteristic that satisfies the quadratic function relationship. Among them, the stress level of the rock is the main factor affecting the fitting effect; (3) under the same confining pressure, with an increase in cycle level, the macroscopic deformation of the rock increases, the accumulation of fatigue damage in the sample increases, and the irreversible deformation of the rock increases, which leads to an increase in energy input and dissipation; (4) in terms of elastic energy and dissipation energy, elastic energy plays a dominant role. In the initial cycle, the rock is destroyed, and the rock energy loss is great. After the second cycle, the input energy is mainly stored in the rock in the form of elastic energy, and only a small part of the input energy is released in the form of dissipation energy; (5) the confining pressure can improve the efficiency of rock absorption and energy storage, enhance the energy storage limit of rock, and limit the dissipation and release of partial energy of rock. The greater the confining pressure, the more evident the limiting effect, and the more significant the dominant position of elastic energy; and (6) the change in the energy dissipation ratio can be divided into three stages: rapid decline stage, stable development stage and rapid rise stage. The greater the increase in dissipation energy, the greater the degree of rock damage. The evolution process of the energy dissipation ratio can reflect the internal damage accumulation process of rock well, which can be used as the criterion of rock instability.

3

Mechanical Property Comparison of Al11Si Wheels Grain Refined by Ti, Nb and MTS

Aydogan F., Dizdar Kerem Can, Sahin Hayati, Mentese E., Dispinar Derya

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 4

14--18

EN

In this work, 25 wheels were cast with three different grain refiners: Al5Ti1B, Al3Nb1B and MTS 1582. Samples were machined from the wheels to check the mechanical properties. It was found that Nb grain refinement had the lowest grain size (260 mm) and highest tensile properties (yield strength of 119-124 MPa and ultimate tensile strength of 190-209 MPa). Al5Ti1B and MTS 1582 revealed quite similar results (110 MPa yield and 198 MPa ultimate tensile strength). The fading of the grain refining effect of Al5TiB1 master alloy was observed in both Nb and Ti added castings whereas during the investigated time interval, the fading was not observed when MTS 1582 was used.

4

Effects of SiC Coating of Carbon Fiber on Mechanical Properties in Short Carbon Fiber Reinforced Al Matrix Composite

Jang Jin Man, Ko Se-Hyun, Lee Wonsik

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 4

941--946

EN

A356 Al composites reinforced by short carbon fiber were prepared through the 2-step process: fabrication of a composite precursor and ultrasonication of the precursor melt. The short carbon fibers were coated with 0.15~1.5 μm thick SiC layer by a car-bothermal reaction, and an amount of the carbon fiber reinforcement was determined to be 1.5 vol.% and 4.0 vol.%, respectively. The addition of the carbon fiber increased the hardness of A356 alloy. However, tensile strength did not increase in the as-cast composites regardless of the SiC coating and volume fraction of the carbon fiber, due to the debonding which reduced load transfer efficiency from matrix to fiber at the interface. After T6-treatment of the composites, a significant increase in strength occurred only in the composite reinforced by the SiC-coated short carbon fiber, which was considered to result from the formation of a precipitate improving the Al/SiC interfacial strength.

5

Consolidation and Oxidation of Ultra Fine WC-Co-HfB2 Hard Materials by Spark Plasma Sintering

Park Hyun-Kuk, Oh Ik-Hyun, Kim Ju-Hun, Hong Sung-Kil, Lee Jeong-Han

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 4

997--1000

EN

In this study, a novel composite was fabricated by adding the Hafnium diboride (HfB2) to conventional WC-Co cemented carbides to enhance the high-temperature properties while retaining the intrinsic high hardness. Using spark plasma sintering, high density (up to 99.4%) WC-6Co-(1, 2.5, 4, and 5.5 wt. %) HfB2 composites were consolidated at 1300°C (100°C/min) under 60 MPa pressure. The microstructural evolution, oxidation layer, and phase constitution of WC-Co-HfB2 were investigated in the distribution of WC grain and solid solution phases by X-ray diffraction and FE-SEM. The WC-Co-HfB2 composite exhibited improved mechanical properties (approximately 2,180.7 kg/mm2) than those of conventional WC-Co cemented carbides. The high strength of the fabricated composites was caused by the fine-grade HfB2 precipitate and the solid solution, which enabled the tailoring of mechanical properties.

6

Investigation of steel wire mesh reinforcement method for 3D concrete printing

Liu Miao, Zhang Qiyun, Tan Zhendong, Wang Li, Li Zhijian, Ma Guowei

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 1

406--423

EN

3D concrete printing has received widespread attention and been developed for an increasing number of applications. However, a major challenge facing this technology is an effective way to introduce reinforcement into continuously deposited cementitious material. In this study, different layers of steel wire meshes (SWM) are employed to reinforce the 3D printed structures to improve mechanical capacities. Both destructive (bending, compression and splitting) and non-destructive (using electro-mechanical impedance) tests are employed to characterize the impact of this reinforcement method. The damage accumulation process is measured through the smart PZT patches based on the electro-mechanical impedance method. The results indicate that reinforced 3D-printed components with SWM change their failure modes from brittle to ductile. The peak loads are increased by 59.2–173.3% and the deflection capacity can be increased by more than 11 times than the non-reinforced one. Different mechanical responses of print and cast samples under compression are studied. The splitting tensile strength of wire mesh reinforced concrete is also measured, which is 43.7% higher than the non-reinforced sample. The calculating methods of the cracking moment and ultimate moment of steel wire mesh reinforced 3D printed concrete are presented. Comparison between the calculated and the experimental results verifies the effectiveness in predicting the ultimate moment. Experimental results show that it is feasible and effective to employ steel wire mesh for strength and toughness enhancement of 3D printed structures.

7

Thermally stable biopolymer composites based on poly(3-hydroxybutyrate) modified with linear aliphatic polyurethanes– preparation and properties

Zarzyka Iwona, Czerniecka-Kubicka Anna, Hęclik Karol, Dobrowolski Lucjan, Pyda Marek, Leś Karolina, Walczak Małgorzata, Białkowska Anita, Bakar Mohamed

Acta of Bioengineering and Biomechanics

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2021

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Vol. 23, no. 2

91--105

EN

Purpose: Poly(3-hydroxybutyrate) (P3HB) is a biopolymer, but storing products from P3HB causes the deterioration of their properties leading to their brittleness. P3HB has also low thermal stability. Its melting point almost equals its degradation temperature. To obtain biodegradable and biocompatible materials characterized by higher thermal stability and better strength parameters than the unfilled P3HB, composites with the addition of polyurethanes were produced. Methods: The morphology, thermal, and mechanical property parameters of the biocomposites were examined using scanning electron microscopy, thermogravimetric analysis, standard differential scanning calorimetry, and typical strength machines. Results: Aliphatic polyurethanes, obtained by the reaction of 1,6-hexamethylene diisocyanate and polyethylene glycols, were used as modifiers. To check the influence of the glycol molar mass on the properties of the biocomposites, glycols with a molecular weight of 400 and 1000 g/mol were used. New biocomposites based on P3HB were produced with 5, 10, 15, and 20 wt. % content of polyurethane by direct mixing using a twin-screw extruder. The following property parameters of the prepared biocomposites were tested: degradation temperature, glass transition temperature, tensile strength, impact strength, and Brinell hardness. Conclusions: Improvement of the processing property parameters of P3HB-biocomposites with the addition of aliphatic polyurethanes was achieved by increasing the degradation temperature in relation to the degradation temperature of the unfilled P3HB by over 30 C. The performance property parameters have also been improved by reducing the brittleness compared to the P3HB, as evidenced by the increase in impact strength and the decrease in hardness with an increase in the amount of polyurethane obtained by the reaction of 1,6-hexamethylene diisocyanate and polyethylene glycol with a molecular weight of 400 g/mol (PU400) as modifier.

8

Microstructure evolution and mechanical properties of underwater dry welded metal of high strength steel Q690E under different water depths

Sun Kun, Huc Yu, Shi Yonghua, Liao Baoyi

Polish Maritime Research

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2020

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nr 4

112--119

EN

Q690E high strength low alloy (HSLA) steel has been intensively applied in maritime engineering. Also, the underwater dry welding (UDW) technique has been widely used to repair important offshore facilities. In this paper, joints of Q690E steel were fabricated through single-pass underwater dry welding at three pressures (0, 0.2, and 0.4 MPa). To study the effect of the pressure on the microstructure and mechanical properties of the UDW joint, an optical microscope (OM) and scanning electron microscope (SEM) were used to observe the microstructure and fracture morphology of the welded joints. The electron backscattered diffraction (EBSD) technique was used to analyse the crystallographic features and the crystallographic grain size of the ferrites. The proportion of acicular ferrite (AF) in the UDW joints and the density of low-angle boundaries increase dramatically with the increasing depth of water. The weld metal of UDW-40 shows higher strength because more fine ferrites and low-angle boundaries within UDW-40 impede the dislocation movement.

9

Egg shell as a filler in composite materials - a review

Kamath Sakshi Shantharam, Chandrappa Ravi Kumar

Journal of Mechanical and Energy Engineering

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2020

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Vol. 4, No 4

335--339

EN

Current focus is on polymer and metal matrix composites for their increased mechanical properties. The strength of the composites is further enhanced by incorporating different types of additives which includes fillers, flame retardants, silanes, coupling agents and so on. One such additives is egg shell powder which influences the strength of composites and thus, gains the attention of researchers for its incorporation in composite fabrication. The work is in progress with respect to utilizing waste egg shell in composite fabrication, which not only finds solution for the waste disposal, but also enhances the strength of composites manufactured. This work is the compilation of work done by different researchers with egg shell in composites, so that the need of its utilization in the manufacture of composites will be stronger.

10

Study of Extrusion Temperature on Extrudability of Al-Zn-Cu Based Alloy

Kim Yong-Ho, Yoo Hyo-Sang, Lee Kyu-Seok, Lee Sung-Ho, Son Hyeon-Taek

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 4

1307--1310

EN

In this study, the extrusion characteristics of Al-2Zn-1Cu-0.5Mg-0.5RE alloys at 450, 500, and 550°C were investigated for the high formability of aluminum alloys. The melt was maintained at 720°C for 20 minutes, then poured into the mold at 200°C and hot-extruded with a 12 mm thickness bar at a ratio of 38:1. The average grain size was 175.5, 650.1, and 325.9 μm as the extrusion temperature increased to 450, 500 and 550°C, although the change of the phase fraction was not significant as the extrusion temperature increased. Cube texture increased with the increase of extrusion temperature to 450, 500 and 550°C. As the extrusion temperature increased, the electrical conductivity increased by 47.546, 47.592 and 47.725%IACS, and the tensile strength decreased to 92.6, 87.5, 81.4 MPa. Therefore, the extrusion temperature of Al extrusion specimen was investigated to study microstructure and mechanical properties.

11

Effect of Fe Content on the Mechanical Properties and Thermal Conductivity of the Al-RE Alloys

Yoo Hyo-Sang, Kim Yong-Ho, Son Hyeon-Taek

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 3

1029--1033

EN

In this study, we investigated the effect of Fe addition (0, 0.25, 0.50 and 0.75 wt.%) on the microstructure, mechanical properties and electrical conductivity of as-cast and as-extruded Al-RE alloys. As the Fe element increased by 0 and 0.75wt.%, the phase fraction increased to 5.05, 5.76, 7.14 and 7.38 %. The increased intermetallic compound increased the driving force for recrystallization and grain refinement. The electrical conductivity of Al-1.0 wt.%RE alloy with Fe addition decreased to 60.29, 60.15, 59.58 and 59.13 % IACS. With an increase in the Fe content from 0 to 0.75 wt.% the ultimate tensile strength (UTS) of the alloy increased from 74.3 to 77.5 MPa. As the mechanical properties increase compared to the reduction of the electrical conductivity due to Fe element addition, it is considered to be suitable for fields requiring high electrical conductivity and strength.

12

Characterization of Ceramic Particle Reinforced Titanium Composite Produced Via Powder Metallurgy

Angel D. A., Miko T., Benke M., Gacsi Z.

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 2

515--519

EN

Nowadays, titanium is one of the most popular materials for aeronautical applications due to its good corrosion resistance, formability and strength. In this paper, rutile reinforced titanium matrix composites were produced via powder metallurgy. The steps included high energy ball milling of raw titanium and rutile powders in a planetary ball mill, which was followed by cold-pressing and sintering without external pressure. For the characterization of the milled powders and the sintered composites, scanning electron microscope, X-ray diffraction and compressive strength examinations were carried out. The results showed that the rutile has a strengthening effect on the titanium matrix. 1 wt% rutile increased the compressive strength compared to the raw titanium. Increasing the milling time of the metal matrix decreased the compressive strength values.

13

Properties of Pure Ti Implants Fabricated by Additive Manufacturing

Kim Dong-Jin, Kim Hyung-Giun, Kim Ji-Sun, Song Kuk-Hyun

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 3

959--962

EN

This study was carried out to evaluate the aspect of microstructure and mechanical property development on additive manufactured pure Ti at elevated heat-input. For this work, pure Ti powder (commercial purity, grade 1) was selected, and selective laser melting was conducted from 0.5 to 1.4 J/mm. As a result, increase in heat-input led to the significant grain growth form 4 μm to 12 μm, accompanying with the change of grain shape, correctly widmanstätten structured grains. In addition, Vickers microhardness was notably increased from 228 Hv to 358 Hv in accordance with elevated heat-input, which was attributed to the increased concentration of oxygen and nitrogen mainly occurred during selected laser melting process.

14

The Effect of CaSiAl Modification on the Non-metallic Inclusions and Mechanical Properties of Low-carbon Microalloyed Cast Steel

Kalandyk B., Zapała R., Sobula S., Tęcza G.

Archives of Foundry Engineering

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2019

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iss. 1

47--52

EN

The effect of CaSiAl modification (43-49% Ca, 43-48% Si, 2% Al) on the non-metallic inclusions and mechanical properties of cast low-carbon steel is discussed. Tests were carried out on the cast steel with 0.2% C and micro-additives of V and Nb, used mainly for heavy steel castings (e.g. slag ladles). The modifier in an amount of 1.5 and 3 kg / Mg was introduced to the liquid steel before tapping the metal into a ladle. Test ingots of Y type and a weight of 10 kg were cast and then subjected to a normalizing heat treatment. Using light microscopy and scanning electron microscopy, qualitative and quantitative evaluation of the non-metallic inclusions present in as-cast samples was carried out. Additionally, tests of mechanical strength and impact strength were performed on cast steel with and without the different content of modifier. It was found that increasing the modifier addition affected impact strength but had no significant effect on tensile strength and yield strength. The material with high impact strength had the smallest area fraction of non-metallic inclusions in the microstructure (0.20%). The introduction of modifiers changed the morphology of non-metallic inclusions from dendritic to regular and nodular shapes.

15

The friction influence on stress in micro extrusion

Piwnik J., Mogielnicki K.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 1 spec.

451--454

EN

Manufacturing of metallic parts by forming methods is industrially widespread due to high production rate, high accuracy, dimension’s and shape’s repeatability and good surface quality. The application of metal extrusion methods for the production of micro parts is possible, but there are some technological problems caused by small dimensions. Size effect is appearing. One of size effect symptom in micro extrusion, is a significant influence of rough contact between workpiece and tool while processing. In the case of rough contact without friction, material flows in the vicinity of the die surface. In order to explain more accurately a friction distribution in this area, the plastic wave friction model is proposed. This paper analyses specifications of a metal extrusion in micro scale. Using the friction model, a substitute friction shear factor mz and its influence on extrusion loading curves is determined in relationship to size of asperities.

16

The friction in rod forward and backward micro extrusion

Piwnik J., Mogielnicki K., Gabrylewski M., Baranowski P.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 1 spec.

447--450

EN

Micro parts are increasingly applied in industry because of the trend to miniaturization every day devices. Microforming is a method of manufacturing metal micro elements using a plastic treatment. This kind of production ensures high productivity, shapes and dimensions repeatability and good surface quality. Size effect connected with small dimensions affects changes in treatment processes of micro parts. While forming in micro scale, surface roughness is size independent and does not decrease with decreasing detail dimensions. The article presents schemas for forward and backward extrusion of metal rods. Using FEM, tool’s roughness as a triangle wave has been assumed, taking into account thereby size effect. Influence of roughness on extrusion forces by comparison with traditional flat tools and constant friction shear factor m has been specified. Impact of roughness caused growth of extrusion forces while forward extruding. On the contrary, backward extrusion ensured stable required forces, regardless of a surface structure.