• Journal of the Korean institute of surface engineering
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• v.56 no.2
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• pp.160-168
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• 2023

Recently, investigation on metallization is a key for a stretchable display. Amorphous metal such as Ni and Zr based amorphous metal compounds are introduced for a suitable material with superelastic property under certain stress condition. However, Ni and Zr based amorphous metals have too high resistivity for a display device's interconnectors. In addition, these metals are not suitable for display process chemicals. Therefore, we choose an aluminum based amprhous metal Al-Mo as a interconnector of stretchable display. In this paper, Amorphous Forming Composition Range (AFCR) for Al-Mo alloys are calculated by Midema's model, which is between 0.1 and 0.25 molybdenum, as confirmed by X-ray diffraction (XRD). The elongation tests revealed that amorphous Al-20Mo alloy thin films exhibit superior stretchability compared to pure Al thin films, with significantly less increase in resistivity at a 10% strain. This excellent resistance to hillock formation in the Al20Mo alloy is attributed to the recessed diffusion of aluminum atoms in the amorphous phase, rather than in the crystalline phase, as well as stress distribution and relaxation in the aluminum alloy. Furthermore, according to the AES depth profile analysis, the amorphous Al-Mo alloys are completely compatible with existing etching processes. The alloys exhibit fast etch rates, with a reasonable oxide layer thickness of 10 nm, and there is no diffusion of oxides in the matrix. This compatibility with existing etching processes is an important advantage for the industrial production of stretchable displays.

• Korean Journal of Materials Research
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• v.6 no.2
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• pp.188-196
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• 1996

LiOH 용액에서 핵연료피복관용 Zr합금의 부식이 가속되는 현상을 규명하기 위하여 autoclave를 이용하여 순수물, 다른 농도의 Li 용액 및 여러 가지 알카리 수산화물 조건에서 부식시험을 실시하였다. LiOH 용액에서 부식이 가속되는 현상은 용액 내에 Li 농도가 2.2ppm 이상에서부터 일어나기 시작하며 30ppm 이상에서는 급격한 가속 현상이 일어난다. 부식반응 동안에 발생되는 수소 흡수현상은 220ppm Li에서는 물에 비해 약 2배의 높은 수소흡수율을 나타내며 산화막은 주로 수소화물이 모여 있는 지역에서 우선적으로 성장한다. Li가속 부식기구와 관련하여 본 연구 결과는 지금까지 다른 연구자들이 제안한 부식 기구들과는 일치하지 않았다. LiOH 용액 내에서는 수소흡수와 수소화물 형성이 가속되고 이로 인해 산화막의 성질이 비보호성의 산화막으로 변함으로서 부식은 가속된다는 새로운 모델을 제시하였다.

• Nuclear Engineering and Technology
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• v.45 no.4
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• pp.505-512
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• 2013

Three types of zirconium base alloy were evaluated to study how their work hardening behavior is affected by alloy composition. Repeated-tensile tests (5% elongation at each test) were performed at room temperature at a strain rate of $1.7{\times}10^{-3}s^{-1}$ for the alloys, which were initially controlled for their microstructure and texture. After considering the yield strength and work hardening exponent (n) variations, it was found that the work hardening behavior of the zirconium base alloys was affected more by the Nb content than the Sn content. The facture mode during the repeated tensile test was followed by the slip deformation of the zirconium structure from the texture and microstructural analysis.

• Journal of the Korean institute of surface engineering
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• v.29 no.6
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• pp.628-633
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• 1996

Large saturation magnetization $4pM_s$ is essentially required for soft magnetic thin layers used in magnetic recording devices. Amorphous Co-based alloys and Fe-Co alloys may be regarded as one of the candidates for soft magnetic materials which possess large $4\piM_s$. Some preparation process to improve soft magnetism of these films were performed in this study. Addition of Ta seemed to be effective to change the magnetostriction constant $\lambda$ from positive value to negative one. The magnetoelastic energy $K_e$ is strongly dependent on $\lambda$. $(Co_{95.7}Zr_{4.3})_{100-x}Ta_x$ films with $K_e$ of negative value have sufficiently soft magnetic characteristics. $Fe_{90}Co_{10}$ alloy exhibits extremely large $4\piM_s$, of about 24 kG. Addition of N and Ta to $Fe_{90}Co_{10}$ films improved the soft magnetism of them. The $Fe_{82.0}Co_{7.6}Ta_{10.4}$:N/Ti multilayered films exhibit better soft magnetic properties and better thermal stability than Fe-Co-Ta:N singlelayer films.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.152-152
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• 2017

Titanium and its alloys have been widely used for biomedical applications. However, the use of the Ti-6Al-4V alloy in biomaterial is then a subject of controversy because aluminum ions and vanadium oxide have potential detrimental influence on the human body due to vanadium and aluminum. Hence, recent works showed that the synthesis of new Ti-based alloys for implant application involves more biocompatible metallic alloying element,such as, Nb, Hf, Zr and Mo. In particular, Nb and Hf are one of the most effective Ti ${\beta}$-stabilizer and reducing the elastic modulus. Plasma electrolyte oxidation (PEO) is known as excellent method in the biocompatibility of biomaterial due to quickly coating time and controlled coating condition. The anodized oxide layer and diameter modulation of Ti alloys can be obtained function of improvement of cell adhesion. Silicon (Si) and magnesium (Mg) has a beneficial effect on bone. Si in particular has been found to be essential for normal bone and cartilage growth and development. In vitro studies have shown that Mg plays very important roles in essential for normal growth and metabolism of skeletal tissue in vertebrates and can be detected as minor constituents in teeth and bone. Therefore, in this study, Si and Mg coatings on the hydroxyapatite film formed Ti-29Nb-xHf alloys by plasma electrolyte oxidation has been investigated using several experimental techniques. Ti-29Nb-xHf (x= 0, 3, 7 and 15wt%, mass fraction) alloys were prepared Ti-29Nb-xHf alloys of containing Hf up from 0 wt% to 15 wt% were melted by using a vacuum furnace. Ti-29Nb-xHf alloys were homogenized for 2 hr at $1050^{\circ}C$. The electrolyte was Si and Mg ions containing calcium acetate monohydrate + calcium glycerophosphate at room temperature. The microstructure, phase and composition of Si and Mg coated oxide surface of Ti-29Nb-xHf alloys were examined by FE-SEM, EDS, and XRD.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.337-341
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• 2004

Bulk metallic glasses(BMG) with good mechanical properties have problems that engineering application fields have been limited because of limitation of the alloy size. In order to solving this problem, the friction welding of BMG has been tried using the superplastic-like deformation behavior under the supercooled liquid region. The apparatus for friction welding test was designed and constructed using pneumatic cylinder and gripper based on a conventional lathe. Friction welding have been tried to combination of same BMG alloy and crystalline alloys. The results of welding test were evaluated by X-ray diffraction, measurement of hardness and mechanical properties test. In order to obtain the optimized welding test conditions the temperature of friction interface was measured using Infrared thermal imager.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.42-47
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• 2004

Metallic glasses are amorphous meta-stable solids and are now being processed in bulk form suitable for structural applications including impact. Bulk metallic glasses have many unique mechanical properties such as high yield strength and fracture toughness, good corrosion and wear resistance that distinguish them from crystalline metals and alloys. However, only a few studies could be found mentioning the dynamic response and damage of metallic glasses under impact or shock loading. In this study, we employed a small explosive detonator for the dynamic indentation on a Zr-based bulk amorphous metal in order to evaluate the damage behavior of bulk amorphous metal under impact loading. These results were compared with those of spherical indentation under quasi-static and impact loading. The interface bonded specimens were adopted to observe the appearances of subsurface damage induced during indentation under different loading conditions.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.21 no.1
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• pp.115-147
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• 2023

The Fukushima accident in 2011 revealed some major flaws in traditional nuclear fuel materials under accidental conditions. Thus, the focus of research has shifted toward "accident tolerant fuel" (ATF). The aim of this approach is to develop fuel material solutions that lead to improved reactor safety. The application of protective coatings on the surface of nuclear fuel cladding has been proposed as a near-term solution within the ATF framework. Many coating materials are being developed and evaluated. In this article, an overview of different zirconium-based alloys currently in use in the nuclear industry is provided, and their performances in normal and accidental conditions are discussed. Coating materials proposed by different institutions and organizations, their performances under different conditions simulating nuclear reactor environments are reviewed. The strengths and weaknesses of these coatings are highlighted, and the challenges addressed by different studies are summarized, providing a basis for future research. Finally, technologies and methods used to synthesize thin-film coatings are outlined.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.21 no.1
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• pp.1-8
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• 2023

The major concern in the deep geological disposal of spent nuclear fuels include sulfide-induced corrosion and stress corrosion cracking of copper canisters. Sulfur diffusion into copper canisters may induce copper embrittlement by causing Cu₂S particle formation along grain boundaries; these sulfide particles can act as crack initiation sites and eventually cause embrittlement. To prevent the formation of Cu₂S along grain boundaries and sulfur-induced copper embrittlement, copper alloys are designed in this study. Alloying elements that can act as chemical anchors to suppress sulfur diffusion and the formation of Cu₂S along grain boundaries are investigated based on the understanding of the microscopic mechanism of sulfur diffusion and Cu₂S precipitation along grain boundaries. Copper alloy ingots are experimentally manufactured to validate the alloying elements. Microstructural analysis using scanning electron microscopy with energy dispersive spectroscopy demonstrates that Cu₂S particles are not formed at grain boundaries but randomly distributed within grains in all the vacuum arc-melted Cu alloys (Cu-Si, Cu-Ag, and Cu-Zr). Further studies will be conducted to evaluate the mechanical and corrosion properties of the developed Cu alloys.

• Transactions of the Korean hydrogen and new energy society
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• v.9 no.1
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• pp.16-24
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• 1998

Recently Zr-based $AB_2$ type hydrogen absorbing alloy has received much attention as a negative electrode material for the Ni-MH batteries because of its high capacity. In this study $ZrV_{0.1}Mn_{0.7}Ni_{1.2}$ alloy was chosen and the effects of heat treatment and a partial substitution of the Mo in Mn site on the various electrode properties were investigated. The alloys was prepared by arc melting (as-cast sample). Some of them were heat treated at $1,100^{\circ}C$ for 4 hours. After this they were differentiated by the different cooling rates of slow cooling and quenching. Various electrode characteristics such as activation process, high rate dischargeability and self discharge characteristic were investigated with the three types of electrodes. It was found that heat treated alloys resulted in an increase in plateau flatness of P-C isotherms however both discharge capacity and high rate capability were decreased. And the partial substitution of Mo for Mn in $ZrV_{0.1}Mn_{0.7}Ni_{1.2}$ alloy improved the self-discharge characteristic without the loss of discharge capacity (300mAh/g).