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.

Grain morphology, phase stability and mechanical properties in binary Ti-Al alloys containing 43-52 mo1% Al have been investigated. Isothermal forging was used to control the grain sizes of these alloys in the range of 5 to 350 μm. Grain morphology and volume fraction of α2 phase were observed by optical metallography and scanning electron microscopy. Compressive properties were evaluated at room temperature, 1070 K, and 1270 K in an argon atmosphere. Work hardening is significant at room temperature, but it hardly took place at 1070 K and 1270 K because of dynamical recrystallization. The grain morphologies were determined as functions of aluminum content and processing conditions. The transus curve of α and α+γ shifted more to the aluminum-rich side than was the case in McCullough’s phase diagram. Flow stress at room temperature depends strongly on the volume fraction of the α2 phase and the grain size, whereas flow stress at 1070 K is insensitive to the alloy composition or the grain size, and flow stress at 1270 K depends mainly on the grain size. The α2 phase in the alloys does not increase the proof stress at high temperatures. These observations indicate that improvement of both the proof stress at high temperature and the room temperature ductility should be achieved to obtain slightly Ti-rich TiAl base alloys.

In this study, the glass-forming ability and mechanical properties of newly developed Fe-Mn-Cr-Mo-B-C-P-Si-Al bulk amorphous alloys were investigated, and metalloid elements such as B, C, and P were found to have a strong influence on the properties of the Fe-based amorphous alloys. When the total metalloid content (B, C, and P) is less than 5%, only the crystal phase is formed, but the addition of more than 10% metalloid elements enhances the glass forming ability. In particular, the alloys with 10 % metalloid content exhibit the best combination of very high compressive strength (~2.8 GPa) and superior fracture elongation (~30 %) because they consist of crystal/amorphous composite phases.

In this work, the effects of maleic anhydride (MA) content on mechanical properties of chopped carbon fibers (CFs)-reinforced MA-grafted-polypropylene (MAPP) matrix composites. A direct oxyfluorination on CF surfaces was applied to increase the interfacial strength between the CFs and MAPP matrix. The mechanical properties of the CFs/MAPP composites are likely to be different in terms of MA content. Surface characteristics were observed by scanning electron microscope, Fourier transform infrared spectroscopy, and single fiber contact angle method. The mechanical properties of the composites were also measured by a critical stress intensity factor (KIC). From the KIC test results, the KIC values were increased to a maximum value of 3.4 MPa with the 0.1 % of MA in the PP, and then decreased with higher MA content.

Magnesium alloy is becoming known for the lightest material in the metallic materials. Recently the automotive industry has a variety application to the light weight parts replacement. This study focuses on the mechanical property improving through a tiny amount’s CNT addition into the magnesium alloy as AM60. The CNT material is an arduous combination of the metallic materials. Therefore this study is concentrating on the contact force growth for the CNT material. Consequently, the made CNT is produced by the CVD process using the magnesium catalyst. The CNT material has dispersive with mechanical process into the molten AM60 alloy. The mechanical experiment result that hardness is 18% increasing and tensile strength is 13% increasing, better than the raw AM60 alloy on this investigation.

We performed this study to understand the effect of a single-crystalline anode on the mechanical properties of asdeposited films during electrochemical deposition. We used a (111) single- crystalline Cu plate as an anode, and Si substrates with Cr/Au conductive seed layers were prepared for the cathode. Electrodeposition was performed with a standard 3-electrode system in copper sulfate electrolyte. Interestingly, the grain boundaries of the as-deposited Cu thin films using single-crystalline Cu anode were not distinct; this is in contrast to the easily recognizable grain boundaries of the Cu thin films that were formed using a poly-crystalline Cu anode. Tensile testing was performed to obtain the mechanical properties of the Cu thin films. Ultimate tensile strength and elongation to failure of the Cu thin films fabricated using the (111) single-crystalline Cu anode were found to have increased by approximately 52 % and 37%, respectively, compared with those values of the Cu thin films fabricated using apoly-crystalline Cu anode. We applied ultrasonic irradiation during electrodeposition to disturb the uniform stream; we then observed no single-crystalline anode effect. Consequently, it is presumed that the single-crystalline Cu anode can induce a directional/uniform stream of ions in the electrolyte that can create films with smeared grain boundaries, which boundaries strongly affect the mechanical properties of the electrodeposited Cu films.

목재의 재질특성은 토양, 지형, 기후변화 등의 다양한 환경적 요인이나 임분특성에 의해서 바뀌게 된다. 본 연구에서는 후박나무 목재의 역학적 특성을 임분특성으로 볼 수 있는 지역과 임종에 따라 비교하였다. 지역에 따른 역학적 특성을 비교한 결과 경남 고성이 전남 완도지역에 비하여 높은 값을 나타내었으며 t-검정 결과에서도 유의성이 인정되는 상관관계가 나타났다. 또한 성림 기원에 따른 생장량과 밀도특성을 비교한 결과 후박나무 인공조림지가 후박나무 이차림에 비하여 높은 값을 나타내었으며, 역학적 특성은 전체적으로 후박나무 이차림이 후박나무 인공조림지에 비하여 높은 값을 나타내었으나 t-검정 결과 압축강도를 제외한 나머지 역학적 특성에서는 유의성이 인정되는 상관관계가 나타나지 않았다.

The cold rolling workability and mechanical properties of two new alloys, designed and cast Al-5.5Mg-2.9Si and Al-7Mg-0.9Zn alloys, were investigated in detail. The two alloy sheets of 4 mm thickness, 30 mm width and 100 mm length were reduced to a thickness of 1 mm by multi-pass rolling at ambient temperature. The rolling workability was better for the Al-7Mg-0.9Zn alloy than for the Al-5.5Mg-2.9Si alloy; in case of the former alloy, edge cracks began to occur at 50% rolling reduction, and their number and length increased with rolling reduction; however, in the latter alloy, the sheets did not have any cracks even at higher rolling reduction. The mechanical properties of tensile strength and elongation were also better in the Al-7Mg-0.9Zn alloy than in Al-5.5Mg-2.9Si alloy. Work hardening ability after cold rolling was also higher in the Al-7Mg- 0.9Zn alloy than in the Al-5.5Mg-2.9Si alloy. At the same time, the texture development was very similar for both alloys; typical rolling texture developed in both alloys. These differences in the two alloys can primarily be explained by the existence of precipitates of Mg2Si. It is concluded that the Al-7Mg-0.9Zn alloy is better than the Al-5.5Mg-2.9Si alloy in terms of mechanical properties.

A lean alloy is defined as a low alloy steel with a minimum amount of the alloying element that maintains the characteristics of the sintered alloy. It is well known that the addition of elements such as Cr, P, Si, or Mn improves the mechanical characteristics of the alloy, but decreases the sinterability. The mother alloy is used to avoid an oxidation reaction with the alloying elements of Cr, P, Si or Mn. The purpose of this study is to determine the change in the mechanical properties of Fe-P-Mo and Fe-P-Mn alloys as a result of the addition of Si. In this article, the Fe-P-Mo and Fe-P-Mn alloys to which Si is added are compacted at 7.0 g/cm3 and then sintered in H2-N2 at 1120℃. The P around the macropores and large grains reduces due to the formation of SiO2 as the Si content increases. This is caused by the increase in strength owing to reducing intergranular fracture by suppressing the reaction with oxygen.

The consumption of pre-treated vegetables (including fresh-cut vegetables) has been significantly increased because of their ease of use for cooking. Vegetable cutting machine has been widely utilized for producing fresh-cut vegetables or agricultural products with different sizes; however, its design standard is not specifically established depending on types of agricultural products. Therefore, this study was conducted to determine mechanical properties (compressive and shear force) of targeted agricultural products (radish, carrot, squash, cucumber, shiitake mushroom and sweet potato) for developing multipurpose vegetable cutting machine. According to ASAE standard (s368.3), compressive and shear force of targeted agricultural products were measured by using custom built UTM (universal testing machine). Shape type of samples and speed ranges (5~15 mm/min) of loading rate on bioyield and shear points were varied by targeted agricultural products. The range of averaged bioyield points of targeted agricultural products were between 7.89 and 146.98 N. On the other hands, their averaged shear points were from 22.50 to 53.47 N. Results clearly showed that the bioyield and shear points of targeted agricultural products were thoroughly affected by their components. As accumulating compressive and shear points of agricultural products, it can be technical feasible to establish the design standard and control mechanism of multipurpose vegetable cutting machine.

In this study, the recently developed Al 2013 alloy was T8-tempered and, to improve the strength and corrosionresistance, slight amounts of Zr of 0.2 wt% and 0.5 wt%, respectively, were added and the mechanical properties were analyzed. For microstructure and precipitate analysis, OM observation, XRD analysis, and TEM analysis were performed, and for the mechanical property analysis, hardness and tensile strength tests were done. Also, in order to determine the corrosion rate according to the Zr content, a potentiodynamic polarization test was performed and the properties were compared and analyzed. The size of the precipitate varied with the content of Zr and was finest at Zr content of 0.2 wt%; it grew larger at 0.5 wt%, at which point the hardness value accordingly showed the same trend. On the other hand, as calculated from the aspect of chemical bonding among atoms, it was confirmed that the tensile strength and the corrosion-resistance increased with the same trend.