• Journal of Korea Foundry Society
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• v.28 no.1
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• pp.15-19
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• 2008

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1999.05a
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• pp.148-150
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• 1999

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1998.05a
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• pp.8-8
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• 1998

• The Journal of Advanced Prosthodontics
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• v.6 no.3
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• pp.215-223
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• 2014

PURPOSE. This study aimed to develop a copper-aluminium-nickel alloy which has properties comparable to that of dental alloys used for dental post and core applications with the reasonable cost. MATERIALS AND METHODS. Sixteen groups of experimental copper alloys with variants of 3, 6, 9, 12 wt% Al and 0, 2, 4, 6 wt% Ni were prepared and casted. Their properties were tested and evaluated. The data of thermal, physical, and mechanical properties were analyzed using the two-way ANOVA and Tukey's test (${\alpha}$=0.05). The alloy toxicity was evaluated according to the ISO standard. RESULTS. The solidus and liquidus points of experimental alloys ranged from $1023^{\circ}C$ to $1113^{\circ}C$ and increased as the nickel content increased. The highest ultimate tensile strength ($595.9{\pm}14.2$ MPa) was shown in the Cu-12Al-4Ni alloy. The tensile strength was increased as the both elements increased. Alloys with 3-6 wt% Al exhibited a small amount of 0.2% proof strength. Accordingly, the Cu-9Al-2Ni and Cu-9Al-4Ni alloys not only demonstrated an appropriate modulus of elasticity ($113.9{\pm}8.0$ and $122.8{\pm}11.3$ GPa, respectively), but also had a value of 0.2% proof strength ($190.8{\pm}4.8$ and $198.2{\pm}3.4$ MPa, respectively), which complied with the ISO standard requirement (>180 MPa). Alloys with the highest contents of nickel (6 wt% Ni) revealed a widespread decolourisation zone (5.0-5.9 mm), which correspondingly produced the largest cell response, equating positive control. CONCLUSION. The copper alloys fused with 9 wt% Al and 2-4 wt% Ni can be considered for a potential use as dental post and core applications.

• Journal of Ocean Engineering and Technology
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• v.17 no.5 s.54
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• pp.76-81
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• 2003

Friction welding of GCD45 spheroidal graphite cast iron and 2024 aluminum alloy has been studied, especially in terms of the joint faces and strength of friction welding. For appropriate results of the friction welding of GCD45 graphite cast iron and 2024 aluminum alloy, an insert of A1050 pure aluminum metal was used. The joint strength of the A1050 pure aluminum insert approached the maximum strength of 165.7Mpa, compared to 128MPa for the joint between GCD45 graphite cast iron and A1050 pure aluminum without the insert metal. Maximum strength, 165.7Mpa, was possible for the following optimum conditions: 20MPa for the friction pressure, P1, 60MPa for the upsetting pressure, P2, 1 second for the friction time, t1, 3000rpm for the rotation, N, and 0.3 seconds for the brake time, tB.

• Journal of the Korean Society for Heat Treatment
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• v.7 no.4
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• pp.270-276
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• 1994

The effects of thermomechanical and duplex aging treatment on precipitation behavior were investigated for the 8090 aluminium alloy by tensile test, hardness test, plane-strain fracture toughness test and electron microscope. Both pre-aging stretch and duplex aging with pre-aging stretch were effective to homogenize the distribution of S' phase in this alloys. The latter makes more homogeneous distribution of S' phase than that of the former, but the sizes of S' phase in both specimens are almost same. The size and distribution of 0' phase were not changed by thermomechanical or duplex aging treatment. The strength was increased by thermomechanical treatment, but the elongation was decreased. Duplex aging treatment couldn't change the strength and elongation. Pre-aging stretch and duplex aging with pre-aging stretch have same effect on the strength and elongation. The increase of strength by thermomechanical treatment in 8090 alumunium alloy was caused by homogeneously precipitated S' phase.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.2
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• pp.139-145
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• 2010

Bending fatigue of aluminium alloy was characterized by acoustic nonlinearity of narrow band laser-generated surface wave. The higher harmonic components generated intrinsically by arrayed line laser beam were analyzed theoretically and acoustic nonlinearity was measured successfully on the surface of fatigue damaged aluminium 6061 alloy. The acoustic nonlinearity increased as a function of fatigue cycles and has close relation with damage level. Consequently, the nonlinear acoustic technique of laser-generated surface wave could be potential to characterize surface damages subjected to fatigue.

• Journal of the Korean institute of surface engineering
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• v.51 no.6
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• pp.381-386
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• 2018

In this study, plasma electrolytic oxidation (PEO) method was used to from anodic oxide films on Al alloy and their resistance and morphological characteristics were investigated as a function of film formation voltage and treatment time. Cross-sectional morphology and composition of the PEO films were analyzed by SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive Spectroscopy). The PEO films showed increased surface roughness and thickness with of film formation voltage and treatment time. The wear resistance was found to be the best for the PEO film formed for 5 min at 500V which is attributed to be denser structure relatively and lower surface roughness.

• Journal of Welding and Joining
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• v.33 no.5
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• pp.1-8
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• 2015

Aluminium and its alloys are widely used in brazing various components in automotive industries due to their properties like lightweight, excellent ductility, malleability and formability, high oxidation and corrosion resistance, and high electrical and thermal conductivity. However, high machinability and strength of aluminium alloys are a serious concern during casting operations. The generation of porosity caused by dissolved gases and modifiers affects seriously the strength and quality of cast product. Brazing of Al and its alloys requires careful monitoring of temperature since theses alloys are brazed at around the melting temperature in most of the aluminium alloys. Therefore, the development of low temperature brazing filler alloys as well as superior strength Al alloys for various engineering applications is always in demand. In various heat exchangers and automotive applications, poor strength of Al alloys is due to the inherent porosities and casting defects. The unstable mechanical properties is therefore needed to be controlled by adding various additive elements in the aluminium and its alloys, by a change in the heat treatment procedure or by modifying the microstructure. In this regard, this article reports the effect of various elements added in aluminium alloys to improve microstructure, brazeability, machinability, castability as well as to stabilize the mechanical properties.

• Journal of the Korean Society for Railway
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• v.12 no.4
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• pp.512-517
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• 2009

Extruded aluminium panels have been widely used for railway vehicle structures because -of their light specific weight and other merits. In the past, GMAW (Gas Metal Arc Welding) and GTAW (Gas Tungsten Arc Welding) were mainly used to join aluminium panels. But recently friction stir welding (FSW) is widely used due to its lots of advantage. In this study aluminium A6005 which is used for car body structures was chosen. The influences of main parameters on mechanical properties such as: pin (tool) rotating speed, pin transition speed, shoulder, diameter, pin length and tilting angle were examined. Optical microscope and scanning electron microscope (SEM) observation, micro hardness tests, and tensile tests were carried out.