In this study, an Al-0.7wt%Fe-0.2wt%Mg-0.2wt%Cu-0.02wt%B alloy was designed to fabricate an aluminum alloy for electrical wire having both high strength and high conductivity. The designed Al alloy was processed by casting, extrusion and drawing processes. Especially, the drawing process was done by severe deformation of a rod with an initial diameter of 12 mm into a wire of 2 mm diameter; process was equivalent to an effective strain of 3.58, and the total reduction in area was 97 %. The drawn Al alloy wire was then annealed at various temperatures of 200 to 400 °C for 30 minutes. The mechanical properties, microstructural changes and electrical properties of the annealed specimens were investigated. As the annealing temperature increased, the tensile strength decreased and the elongation increased. Recovery or/and recrystallization occurred as annealing temperature increased, and complete recrystallization occurred at annealing temperatures over 300 °C. Electric conductivity increased with increasing temperature up to 250 °C, but no significant change was observed above 300 °C. It is concluded that, from the viewpoint of the mechanical and electrical properties, the specimen annealed at 350 oC is the most suitable for the wire drawn Al alloy electrical wire.

In this study, Bi-Sb-Te thermoelectric materials are produced by mechanical alloying (MA) and spark plasma sintering (SPS). To examine the influence of the milling atmosphere on the microstructure and thermo-electric (TE) properties, a p-type Bi-Sb-Te composite powder is mechanically alloyed in the presence of argon and air atmospheres. The oxygen content increases to 55% when the powder is milled in the air atmosphere, compared with argon. All grains are similar in size and uniformly, distributed in both atmospheric sintered samples. The Seebeck coefficient is higher, while the electrical conductivity is lower in the MA (Air) sample due to a low carrier concentration compared to the MA (Ar) sintered sample. The maximum figure of merit (ZT) is 0.91 and 0.82 at 350 K for the MA (Ar) and MA (Air) sintered samples, respectively. The slight enhancement in the ZT value is due to the decrease in the oxygen content during the MA (Ar) process. Moreover, the combination of mechanical alloying and SPS process shows a higher hardness and density values for the sintered samples.

In this study we manufacture a Ni-Cr-B-Si +WC/12Co composite coating layer on a Cu base material using a laser cladding (LC) process, and investigate the microstructural and mechanical properties of the LC coating and Ni electroplating layers (reference material). The initial powder used for the LC coating layer is a powder feedstock with an average particle size of 125 μm. To identify the microstructural and mechanical properties, OM, SEM, XRD, room and high temperature hardness, and wear tests are implemented. Microstructural observation of the initial powder and LC coating layer confirm the layer is composed mainly of γ-Ni phases and WC and Cr23C6 carbides. The measured hardness of the LC coating and Ni electroplating layers are 653 and 154 Hv, respectively. The hardness measurement from room up to high temperatures of 700°C result in a hardness decrease as the temperature increases, but the hardness of the LC coating layer is higher for all temperature conditions. Room temperature wear results show that the wear loss of the LC coating layer is 1/12 of the wear level of the Ni electroplating layer. The measured bond strength is also greater in the LC coating than the Ni electroplating.

PURPOSES: The main distress of asphalt pavements in monsoon climate regions are caused by water damage and plastic deformation due to repeated rain season and increased heavy vehicle traffic volume. In this study, the mechanical properties of polymer-modified warm mix asphalt (PWMA) materials are evaluated to use in monsoon climate regions such as Indonesia. METHODS: Comprehensive laboratory tests are conducted to evaluate moisture resistance and permanent deformation resistance for three different asphalt mixtures such as the Indonesian conventional hot-mix asphalt (HMA) mixture, the polymer-modified asphalt mixture, and the polymer-modified warm mix asphalt (PWMA) mixture. Dynamic immersion test and indirect tensile strength ratio test are performed to evaluate moisture resistance. The wheel tracking test is performed to evaluate rutting resistance. Additionally, the Hamburg wheel tracking test is performed to evaluate rutting and moisture resistances simultaneously. RESULTS: The dynamic immersion test results indicate that the PWMA mixture shows the highest resistance to moisture. The indirect tensile strength ratio test indicates that TSR values of PWMA mixture, Indonesian PMA mixture, and Indonesian HMA mixture show 87.2%, 84.1%, and 67.9%, respectively. The wheel tracking test results indicate that the PWMA mixture is found to be more resistant to plastic deformation than the Indonesian PMA. The dynamic stability values are 2,739 times/mm and 3,150 times/mm, respectively. Moreover, the Hamburg wheel tracking test results indicate that PWMA mixture is more resistant to plastic deformation than Indonesian PMA and HMA mixtures. CONCLUSIONS: Based on limited laboratory test results, it is concluded that rutting resistance and moisture susceptibility of the PWMA mixture is superior to Indonesian HMA and Indonesian PMA mixtures. It is postulated that PWMA mixture would be suitable for climate and traffic conditions in Indonesia.

리파아제 및 프로테이나아제와 같은 생분해성 효소는 지방산 에스테르 및 트리글리 세라이 드뿐만 아니라 지방족 폴리에스테르를 가수 분해가 가능하다. 본 연구에서는 생분해성 효소가 자연 환경 에서 PLA, 옥수수 전분 및 폴리에틸렌글리콜 등의 천연 지방족 폴리 물질이 분해에 중요한 역할인 생 분해성을 측정했다. 본 실험에서는 PLA, PLA와 폴리에틸렌아크릴레이트, PLA 그라프트 중합체인 폴리 에틸렌글리콜아크릴레이트를 사용한 PLAcoPolyethylene의 생분해성에 대해 실험하였다. 생분해성 고분 자를 합성할 때. 이들의 기계적 특성은 생분해성도, 열적특성, 실시간으로 폴리머 수지의 전기적 모니터 링을 통해 실험측정 결과, BOD와 PLAcoPolyethylene의 생분해도는 PLA와 그라프트 공중합된 폴리에 틸렌아크릴레이트는 다른 시료보다 낮은 속도로 측정되었다.

PVA 부직포의 방염성을 향상시키기 위하여 POCl3로 방염처리하였다. POCl3로 처리한 PVA 부직포의 물리적 및 열적 특성을 측정하고 분석하였다. 개질한 PVA 부직포는 대부분 물에 용해하지 않았으나 수축과 스웰링 특성을 보 였다. POCl3로 방염처리한 PVA 부직포의 열적 특성이 우수하고 방염특성이 원시료 보다 많이 우수한 것을 확인하였다. 그라프트 비와 염색성 사이의 선형관계는 PVA 부직포의 히드록시기와 POCl3가 공유결합으로 연결된 것에 기인하는 것 으로 분석되었다.

This study aims to analyze the changes in the mechanical properties of interlock fabrics knitted with three types of fibers (i.e., cotton, wool, and polyester) by bonding fusible interlinings with varying deniers (i.e., 10D, 20D, and 30D) for a 3D virtual try-on system. We experimented with four properties and thicknesses of twelve specimens of interlining bonded knitted fabrics including face fabrics and interlinings. The results showed that the tensile property changed values (i.e., LT increased, and WT and RT decreased) according to the denier of interlinings; however, the change was slight. On the other hand, the bending property increased significantly as the denier of the interlining increased on both the wale and the course. Among shearing properties, the value of G increased as the denier of the interlining increased on both the wale and the weft; however, 2HG decreased. Additionally, changes in the compression property varied according to the fibers and the denier of the interlinings. The thickness of the knitted fabrics increased or decreased slightly by bonding the interlining. based on these results, we conclude that the 3D virtual system users need to reflect these numerical changes of interlock fabrics by bonding interlinings when they perform fitting tasks on the screen to accurately express the to accurately express the manufacturing conditions of the real garment.

This study aims to analyze the changes in the mechanical properties of interlock fabrics knitted with three types of fibers (i.e., cotton, wool, and polyester) by bonding fusible interlinings with varying deniers (i.e., 10D, 20D, and 30D) for a 3D virtual try-on system. We experimented with four properties and thicknesses of twelve specimens of interlining bonded knitted fabrics including face fabrics and interlinings. The results showed that the tensile property changed values (i.e., LT increased, and WT and RT decreased) according to the denier of interlinings; however, the change was slight. On the other hand, the bending property increased significantly as the denier of the interlining increased on both the wale and the course. Among shearing properties, the value of G increased as the denier of the interlining increased on both the wale and the weft; however, 2HG decreased. Additionally, changes in the compression property varied according to the fibers and the denier of the interlinings. The thickness of the knitted fabrics increased or decreased slightly by bonding the interlining. based on these results, we conclude that the 3D virtual system users need to reflect these numerical changes of interlock fabrics by bonding interlinings when they perform fitting tasks on the screen to accurately express the to accurately express the manufacturing conditions of the real garment.

In the present work, we use multiwall carbon nanotubes (MWCNT) as the starting material for the fabrication of sintered carbon steel. A comparison is made with conventionally sintered carbon steel, where graphite is used as the starting material. Milling is performed using a horizontal mill sintered in a vacuum furnace. We analyze the grain size, number of pores, X-ray diffraction patterns, and microstructure. Changes in the physical properties are determined by using the Archimedes method and Vickers hardness measurements. The result shows that the use of MWCNTs instead of graphite significantly reduces the size and volume of the pores as well as the grain size after sintering. The addition of Y2O3.to the Fe-MWCNT samples further inhibits the growth of grains.

Unidirectionally solidified TiAl alloys were prepared by optically-heated floating zone method at growth rates of 10 to 70 mm/h in flowing argon. The microstructures and tensile properties of these crystal bars were found to depend strongly on the growth rate and alloy composition. TiAl alloys with composition of 47 and 50 at.%Al grown under the condition of 10 mm/h showed Ti3Al(α2)/TiAl(γ) layer structures similar to single crystals. As the growth rate increased, the alloys with 47 and 50 at.%Al compositions showed columnar-grain structures. However, the alloys fabricated under the condition of 10 mm/ h had a layered structure, but the alloy with increased growth rate consisted of γ single phase grains. The alloy with a 53 at.%Al composition showed a γ single phase regardless of the growth rate. Room-temperature tensile tests of these alloys revealed that the columnar-grained material consisting of the layered structure showed a tensile ductility of larger than 4 % and relatively high strength. The high strength is caused by stress concentration at the grain boundaries; this enhances the secondary slip or deformation twinning across the layered structure in the vicinity of the grain boundaries, resulting in the appreciable ductility.

The resistance of metallic materials to ballistic penetration generally depends on a number of parameters related to projectile, impact, and armor plate. Recently, armor materials have been required to have various properties such as hardness, strength, and impact toughness in order to maintain an excellent ballistic resistance even after impact. In the present study, the influence of tempering on the microstructure and mechanical properties of an ARMOX 500T armor steel plate was investigated and then compared with those of S45C and SCM440 steels. As the tempering temperature increased, the hardness and strength gradually decreased, whereas the ductility and impact toughness clearly increased because the hardness, tensile, and impact properties were affected by the microstructural evolution and precipitation occurring during tempering. On the other hand, temper embrittlement appeared at tempering temperatures of 300 to 400 °C for the impact specimens tested at low temperature.

The compressive strength and electrical resistance of pitch-based carbon fiber (CF) in cementitious materials are explored to determine the feasibility of its use as a functional material in construction. The most widely used CFs are manufactured from polyacrylonitrile (PAN-based CF). Alternatively, short CFs are obtained in an economical way using pitch as a precursor in a melt-blown process (pitch-based CF), which is cheaper and more eco-friendly method because this pitch-based CF is basically recycled from petroleum residue. In the construction field, PAN-based CFs in the form of fabric are used for rehabilitation purposes to reinforce concrete slabs and piers because of their high mechanical properties. However, studies have revealed that construction materials with pitch-based CF are not popular. This study explores the compressive strength and electrical resistances of a cement paste prism using pitch-based CF.

In this study, we investigate the mechanical and metallurgical properties of the gas metal arc welding. According to flux cored arc welding parameters during welding ATOS80, improving the working conditions of the welding industry to use high strength steel ATOS80 we propose to. Weld test is the tensile strength, yield strength, elongation, hardness, brittleness, such as macro-structure check of the mechanical properties and the weld, the microstructure inspection, defects of the weld subjected to radio-graphic inspection and tissue after welding the test pieces according to the condition variable comparative analysis was investigated by the state.

This study was carried out to evaluate the developed microstructures and mechanical properties of friction welded A6063 alloy. For this work, specimens were prepared at a size of 12 mm Ø × 80 mm, and friction welding was carried out at a rotation speed of 2,000 RPM, friction pressure of 12 kgf/cm² and upset pressure of 25 kgf/cm². To perform an analysis of the grain boundary characteristic distributions, such as the grain size, orientation and misorientation angle distributions, the electron back-scattering diffraction method was used. In addition, in order to identify the dispersed intermetallic compounds of the base and welded materials, transmission electron microscopy was used. The experimental results found that the application of friction welding on A6063 led to significant grain refinement of the welded zone relative to that of the base material. Besides this, intermetallic compounds such as AlMnSi and Al2Cu were found to be dispersed with more refined size relative to that of the base material. This formation retains the mechanical properties of the welds, which results in the fracture aspect at the base material zone. Therefore, based on the developed microstructures and mechanical properties, the application of friction welding on A6063 could be used to obtain a sound weld zone.

Numerous studies have been performed on the nutritional properties and health benefits of rice bran. However no previous reports have investigated rice bran-derived products as a biomaterial for bone formation. Thus, the aim of this study was fabricate composite filaments by combining the agricultural by-product rice bran and polycaprolactone (PCL), which has high biodegradability. It is suggest a possibility as a high value-added biomaterial capable of utilizing 3D printing. First, In order to investigate the optimal ratio of rice bran and PCL, the mixing ratios were set to 0%, 10%, 20%, 50% respectively, and the mixed filaments were defined as r-PCL filaments. The r-PCL filament was analyzed by FE-SEM and EDX for morphological characteristics and mechanical characteristics were analyzed by stress-strain, water contact angle, cytotoxicity test. Our findings confirm the possibility of manufacture environmentally friendly composite bio-filaments for FDM (Fused Deposition Modeling) based 3D printing technology. Thus, we could establish biomimetic scaffolds based on bio-printer filaments mixed with agricultural by-product.

Biodegradable epoxy (B-epoxy) was prepared from diglycidyl ether of bisphenol A and epoxidized linseed oil. The mechanical properties of B-epoxy composites reinforced with multi-walled carbon nanotubes (MWCNTs/B-epoxy) were examined by employing dynamic mechanical analysis, critical stress intensity factor (KIC) tests, and impact strength tests. The electromagnetic interference shielding effectiveness (EMI-SE) of the composites was evaluated using reflection and absorption methods. Mechanical properties of MWCNTs/B-epoxy were enhanced with an increase in the MWCNT content, whereas they deteriorated when the MWCNT content was >5 parts per hundred resin (phr). This can likely be attributed to the entanglement of MWCNTs with each other in the B-epoxy due to the presence of an excess amount of MWCNTs. The highest EMI-SE obtained was ~16 dB for the MWCNTs/B-epoxy composites with a MWCNT content of 13 phr at 1.4 GHz. The composites (13 phr) exhibited the minimum EMI-SE (90%) when used as shielding materials at 1.4 GHz. The EMI-SE of the MWCNTs/B-epoxy also increased with an increase in the MWCNT content, which is a key factor affecting the EMI-SE.

The effects of ammonia-treated graphene oxide (GO) on composites based on epoxy resin were investigated. Ammonia solutions of different concentrations (14–28%) were used to modify GO. Nitrogen functional groups were introduced on the GO surfaces without significant structural changes. The ammonia-treated GO-based epoxy composites exhibited interesting changes in their mechanical properties related to the presence of nitrogen functional groups, particularly amine (C-NH2) groups on the GO surfaces. The highest tensile and impact strength values were 42.1 MPa and 12.3 J/m, respectively, which were observed in an epoxy composite prepared with GO treated with a 28% ammonia solution. This improved tensile strength was 2.2 and 1.3 times higher than those of the neat epoxy and the non-treated GO-based epoxy composite, respectively. The amine groups on the GO ensure its participation in the cross-linking reaction of the epoxy resin under amine curing agent condition and enhance its interfacial bonding with the epoxy resin.