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Porous Fe-Cu-C alloy was sintered by Pulsed Current Activated Sintering(PCAS) method within 10 min from horizontal ball mill mixture. The relative density of Fe-20wt.%Cu-0.8wt.%C alloy fabricated by PCAS method was 91%. The average hardness of the Fe-20wt.%Cu-0.8wt.%C alloy was HRB 92. The phase analysis, microstructure and composition information of the sintered alloy were investigated by using XRD, FESEM, EDAX.

It’s very important to find the most appropriate adhesion technique available, taking into consideration factors such as biocompatibility, non-corrosiveness, mechanical stability, etc. Laser welding is the best choice you can make because from a mechanical viewpoint, a laser welded surface has better particle structure than does a casted particle structure. Furthermore, it requires no additional material and the same metal alloy which is used when casting can be used. Therefore, the resulting mixture will consist of a single alloy, instead of utilizing different alloy combinations. Another benefit is the low economic cost. The most beneficial aspects of laser welding is that it is biologicallly friendlly, doesn't require soldering, can fuse different metal alloys together, and can weld on heat-sensitive spots(E.g. around resin or ceramic). A consistent strong pulse is possible. This technique is capable of welding on master models and creates accurate welds. It is capable of due to its stronger, non-corrosive microscope, which allows 25times magnification during the soldering process. This is possible because of its high stability from the tiny particle structure.

Purpose: The purpose of this study was to investigate to effect of the electro-polishing condition according to electrolyte temperature and current and polishing time on surface morphology and composition by scanning electron microscopy(SEM) and energy dispersive X-ray spectrometer(EDS) in dental casting Co-Cr-Mo alloys. Methods: 16 specimens were divided into 4 groups which have each 4 specimens. The size of specimens were 10 wide and 5 height. the electro-polishing of specimens are by polishing solution temperature and times in Co-Cr- Mo alloy by SEM and EDS analysis. Results: The results shows that most smooth surface is obtained when electro-polishing is performed at 49 for 30-40sec with electro gap of 10mm and 8 voltage. Conclusion: The morphologies of specimens after electro-polishing were scratch absent and significant between at 40 for 45sec and at 49 for 45sec.

We fabricate high-entropy alloy (HEA) Ta1/6Nb2/6Hf1/6Zr1/6Ti1/6 superconducting (SC) thin films via a pulsed laser deposition method. Two targets are prepared using arc melting, each followed by sintering at different temperatures: 550°C and 700°C for 12 hours. The films, HEA550 and HEA700, are deposited on c-cut Al2O3 substrates at a substrate temperature of 520°C, using the targets sintered at 550°C and 700°C, respectively. The SC transition temperature (Tc) of HEA700 is 6.88 K, slightly higher than that of HEA550 (= 6.27 K). Both films exhibit similar upper critical field (Hc2) at 0 K, with 11.34 T for HEA550 and 11.40 T for HEA700. Notably, HEA700 exhibits a large critical current density (Jc) of approximately 4.4 MA/cm2 and 3.5 MA/cm2 at 2.0 K and 4.2 K, respectively, accompanying by a predominance of normal point pinning. These results indicate that the targets prepared by arc melting are beneficial for achieving a large Jc in HEA SC thin films, thus providing new avenues for improving SC critical properties of HEA thin films for their practical applications.

The Small Punch Test (SPT) was developed to evaluate the softening and embrittlement of materials such as power plants and nuclear fusion reactors by taking samples in the field. Specimens used in the SPT are very thin and small disk-shaped compared to specimens for general tensile test, and thus have economic advantages in terms of miniaturization and repeatability of the test. The cryogenic SPT can also be miniaturized and has a significantly lower heat capacity than conventional universal test machines. This leads to reduced cooling and warm-up times. In this study, the cryogenic SPT was developed by modifying the existing room temperature SPT to be cooled by liquid nitrogen using a super bellows and a thermal insulation structure. Since the cryogenic SPT was first developed, basic experiments were conducted to verify the effectiveness of it. For the validation, aluminum alloy 6061- T6 specimens were tested for mechanical properties at room and cryogenic temperature. The results of the corrected tensile properties from the SPT experiment results were compared with known room temperature and cryogenic properties. Based on the correction results, the effectiveness of the cryogenic SPT test was confirmed, and the surface fracture characteristics of the material were analyzed using a 3d image scanner. In the future, we plan to conduct property evaluation according to the development of various alloy materials.

This study has looked at the antibacterial characteristic of the Brassware dish that has been many issues until this presents and experimentally confirmed after knowing that there were antibacterial effecting as the metal ion influenced the cell membrane of the germ. Based on this fact, we tried to known the tendency of antibacterial effect change by the creation of the alloy. This study proceeded the test by cutting the zinc and tin after producing alloy each in a different composition ratio mainly on copper. Each metal was put into a vial with the liquid medium that colon bacterium was cultivated and cultivated again in the petrifilm with certain term of time and observed the number of colonies after 24 hours. Antibacterial effect test was implemented 3 times and was proved that Cu-Sn 30wt% had high antibacterial effect by discovering the structural distortion in the copper alloy by using XRD.

Outdoor copper alloy is exposed to the atmospheric environment, accelerating corrosion progress compared with indoor copper alloy. In order to prevent corrosion, the outdoor copper alloy is coated with wax to block external corrosion factors. However, corrosion of the inside of the coating film is highly likely to continue without the internal corrosion prevention treatment. B.T.A, which is used as a copper alloy water-soluble corrosion inhibitor, has a high possibility of being harmful to the human body and is mainly used to treat excavated artifacts. This study had selected the water-soluble corrosion inhibitor, which was easier to use than the existing wax and B.T.A being used in corrosion inhibition treatment for outdoor copper alloy. A comparative study was conducted on B.T.A, which is a water-soluble corrosion inhibitor used on excavated artifacts, and VCIⓇ, RusⓇ, and L-cys, an amino acid corrosion inhibitor, used for tin bronze test pieces. The experimental method was conducted for a certain period of time with the salt, acid, and air pollution affecting the corrosion of outdoor copper alloy. Based on experiment results, it was concluded that the best water - soluble copper alloy corrosion inhibitor in the atmospheric environment is VCIⓇ. and it could be considered to be applied in replacement of B.T.A due to its low harmfulness. In addition, VCIⓇ is judged to serve as a corrosion inhibitor for outdoor copper alloy because it showed the best result even in the outdoor exposure test which is a real atmospheric environment.

Aluminum alloys are extensively used in civil aircraft due to their lightweight, high strength, and excellent formability. However, their susceptibility to corrosion and corrosion fatigue poses a significant maintenance challenge in aviation environments. This study explores the effec-tiveness of ultrasonic nanocrystal surface modification (UNSM) technology in enhancing the corro-sion fatigue strength of Al7075-T6 alloy. Specimens were subjected to controlled corrosion condi-tions and treated with UNSM either before or after corrosion exposure. Corrosion fatigue tests re-vealed that UNSM treatment significantly increased fatigue life—by over 140 times compared to untreated corroded specimens—by inducing deep compressive residual stress, increasing surface hardness, and refining surface structure. These results highlight UNSM's potential to delay crack initiation and propagation in corrosive environments, offering a promising surface enhancement strategy for aircraft aluminum alloys.

High-entropy alloys (HEAs) consist of five or more principal elements with atomic fraction between 5 % and 35 %, randomly distributed throughout the lattice points. Recently, a simple body-centered cubic structure HEA superconductor, Ta1/6Nb2/6Hf1/6Zr1/6Ti1/6, was discovered and classified as a type-II superconductor with a critical temperature of approximately 8 K. Ta-Nb-Hf-Zr-Ti HEA superconductors exhibit a large critical current density of 1 MA cm-2 and demonstrate robust superconductivity against irradiation-induced disorder. We have synthesized HEA superconductors based on the composition Ta1/6Nb2/6Hf1/6Zr1/6Ti1/6 with various Ce doping concentrations (0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 4 wt%, 8 wt%), investigating the effects of Ce addition on the crystal structure and superconductivity. X-ray diffraction and energy dispersive x-ray spectroscopy results indicate the complex Ce addition effects on the crystals. Notably, while the superconducting transition temperature remains largely unaffected by the presence of magnetic impurities, it is found to be closely related to the lattice constant, which changes with varying Ce doping concentrations.

Magnesium alloy is a light material but has a strong characteristic. However, its high corrosive and monotonous color interrupts the magnesium alloy from commercialization. In this research we have studied the process of improving magnesium corrosion and its esthetic function. After the process for cleaning and etching, the magnesium alloy was put on a panel and ultrapure water on Teflon airtight container, and then heated in a specific condition. After that, the change of color at the surface was observed. It was found out that the surface color changed after it was heated in a dye. Besides, Lauric acid is widely known in improving the hydrophobic property. We observed it on a specific condition, and the result shows that higher contact angle appeared above the surface when it was heated in high temperatures and for longer times. Subsequently it improved its higher hydrophobicity. The tensile strength was measured by 11.0 Mpa in this result. It was found that this research can be used as a basic data on the development of magnesium components and materialize color.

Purpose: The purpose of this study was to evaluate bond strength of Metal Disk alloy and casting alloy. Methods: Metal specimens were divided into 4 groups for each alloy. Three point flexural test were used to measure the bond strength of CAD/CAM metal alloy and casting alloy. Statistical analysis was done using the Statistical Package for Social Sciences version 19.0 for Windows. As for the analysis methods, the study used Kruskal-Wallis test. Results: The average bonding strengths of Group 1 to porcelain was 36.7±9.90 MPa, Group 2 to porcelain was 37.68±4.51 MPa, Group 3 to porcelain was 36.43±6.57 MPa, Group 4 to porcelain was 42.88±6.81 MPa, Each group was not significantly different. Conclusion: Bond strength of Casting alloy is equal to or higher than bond strength of CAD/CAM Metal Disk alloy. Alloy clinical bond strength is 25 MPa, So CAD/CAM Metal Disk alloy can be used as dental material.

Purpose: The aim of this study measured and compared the marginal and internal fit of metal cores with two base metal alloy (Ni-Cr alloy(non-beryllium), Co-Cr alloy). Methods: Maxillary right first molar abutment fabricated by titanium was prepared for this study. Impressions(10ea) were made from titanium model, and study models were poured with improved dental stone. Wax cores of twenty were prepared for burn-out and casting. Ten wax cores cast Ni-Cr alloy(non-Be), and finally ten cast Co-Cr alloy. Marginal and internal fit of cores was evaluated using silicone replica technique and digital microscope(x160). The data were statistically analyzed with the independent samples t-test ( <.05). Results: Mean(standard deviation, SD) marginal and internal fit total size of Ni-Cr alloy(non-Be) group was 73.3(14.4) and of Co-Cr alloy group 65.6(17.4) . The marginal and internal fit total size of Ni-Cr alloy group(non-Be) was statistically significantly greater than that of Co-Cr alloy group (P=.004). Conclusion: Co-Cr alloy cores in this study had a better marginal fit than Ni-Cr alloy(non-Be) cores.

This study is related to the development of lightweight automotive materials that were carried out to develop eco-friendly vehicles worldwide. High-strength aluminum alloy is used as one of the significant lightweight materials in the field of transportation machinery, and it is used as a lightweight material in various areas, including automobiles. The A356 alloy used in this study is an excellent aluminum alloy material that has widely used as a high strength aluminum alloy material in various forming methods. In this study, to examine the characteristics of the two alloys in which Mn and Sr elements were added to the A356 alloy and the A356 alloy, both alloys were manufactured by metal mold casting, which is a gravity casting method. The obtained specimens were heat-treated under the same conditions. In this study have investigated of the microstructure analysis, thermal analysis, crystal phase analysis, and mechanical property evaluation were performed to confirm how the added Mn and Sr elements influenced the microstructure, precipitate formation, and mechanical properties.

강은 자동차 제조업체 및 전기 제품에 많이 사용되고 있으나 부식으로 많은 문제점이 발생한다. 이러한 부식문제를 해결하기 위해 강 위에 아연전기도금을 두껍게 하고 있다. 그러나 아연 도금의 두께가 두꺼워지면 부품 제조 시 크렉이 발생하기 쉬우며, 이로 인해 부식이 더욱더 악화될 수 있다. 이러한 부식 문제를 해결하기 위해 아연과 크롬합금도금에 관심이 집중되고 있다. 본 연구에서는 염화욕에서 합금도금의 조성에 미치는 전해조건의 영향을 조사하였다. 전류밀도가 증가함에 따라 Zn함량이 감소하고 Cr함량은 증가하였다. 전해액 온도가 증가함에 따라 Zn함량이 감소하고 Cr함량은 증가하였으며, 그 결과는 음극 분극곡선으로 가지고 해석되었다.

The steel has been used in modern industry, car maker and electric appliance. The steel have some problem, specially corrosion problem. To solve corrosion problem, Zn electrodeposit on steel have been adapted. Recently, The modern industry asks to increase corrosion resistance. Naturally, Increasing corrosion resistance increases the thickness of Zn electrodeposit. But increasing thickness of Zn electrodeposit has some problems. In making part, There are some crack. This crack cause to decrease corrosion resistance. To solve this problem, it is interested in Zn Based alloy electrodeposit such as Zn-Cr. Here, the influence of the electrolytic conditions on the composition of the alloy plating in the chloride bath was investigated. The results are explained by the cathode overvoltage curve of Cr and Zn. As the current density of the cathode increases, Zn content of electrodeposit decrease and Cr content of electrodeposit increase. As the temperature of the electrolyte increases, Zn content of electrodeposit decrease and Cr content of electrodeposit increase.