• 대한기계학회논문집
• /
• 제18권5호
• /
• pp.1096-1105
• /
• 1994

A hypereutectic Aluminum-Silicon Alloy is widely used in the parts of automobile because of high-resistance and good strength. In this study, the cutting of hypereutectic A1-Si alloy for economical production was investigated by simulation. Tool life and the extraction rate of Si particles is inversely proportional to the depth of cut. When decreasing the depth of cut, the reduction of single crystal diamond tool cost and tool change time is achieved.

• International Journal of Precision Engineering and Manufacturing
• /
• 제2권3호
• /
• pp.5-10
• /
• 2001

Due to the development of high-strength fibers and adhesives, it is now possible to repair cracked metallic plates by bonding reinforced patches to the plate over the crack. In this study, pre-cracked aluminum 6061-T6 alloy plates repaired with bonded carbon/epoxy composite patch are applied to investigate the effect of various patch shapes on the tensile strength and the fatigue behavior of the structure. A non-patch-boned cased and 2 type-50$\times$50, 40$\times$20 mm-composite patch-bonded cases were tested to obtain fracture loads and fatigue crack growth rate. The results showed that the patch-bonded repair improves the static strength by 17% and the fatigue life by 200% compared to non-repaired case. It means that patch-boned repair is more effective in the fatigue life. It was also revealed that the patching method along crack growth direction is more efficient in cost and weight reduction. By observing the fractography, patch-bonded repair specimens demonstrated zigzag fracture patterns compared with the non-patched specimens, which shows a typical ductile fracture.

• 한국주조공학회지
• /
• 제30권4호
• /
• pp.151-156
• /
• 2010

The high-strength low-alloy (HSLA) steels have low carbon contents (0.05~0.25% C) in order to produce adequate formability and weldability, and they have manganese contents up to 1.7%. Small quantities of silicon, chromium, nickel, copper, aluminum, molybdenum are used in various combinations. The results contained in this paper can provide the valuable information on the development of $-40^{\circ}C$ low temperature HSLA. Furthermore, the present experimental data will provide important database for casting steel materials of the offshore structure.

• 대한기계학회논문집A
• /
• 제24권5호
• /
• pp.1146-1154
• /
• 2000

Fatigue strength of NiAl and Ni$_3$Al particulate reinforced aluminum alloy composites fabricated by the diecasting method was examined at room and elevated temperatures. The results were compared wit h that of SiC particulate reinforced one. The particulate reinforced composites showed some improvement in the static and fatigue strength at elevated temperatures when compared with that of Al alloy. The composites reinforced by intermetallic compound particles showed good fatigue strengths at elevated temperatures especially $Ni_3AI_{p}/Al$ alloy composite showed good fatigue limit up to high temperature of 30$0^{\circ}C$. Adopting intermetallic compound particle as a reinforcement phase, it will be possible to develop MMC representing better fatigue property at elevated temperature.

• 열처리공학회지
• /
• 제33권2호
• /
• pp.49-56
• /
• 2020

Magnesium alloy is a metal with high specific strength and light weight, and is attracting attention as a next generation metal for environmentally friendly automobiles and transportation equipment. However, magnesium alloys have a problem of degrading formability due to the basal texture developed during processing, and their application is limited. Although active researches on the control of textures have been conducted in order to minimize this problem, there is a lack of research on the formation of microstructures and textures according to elemental differences. In this study, AZ61 and AZ80 magnesium alloys were selected to investigate the effects of aluminum addition on the microstructure development of magnesium alloys. This research has proven that the increase of the rolling rate results in the decrease of the average grain size of the two alloys, the increase of the hardness, and the increase of the fraction of twins. As shown on this research below, the basal texture developed strongly as the rolling ratio increased. On the other hand, this research also has proven that the two alloys exhibited different texture strength and distribution tendencies, which could be due to the effects of aluminum addition on work hardening, grain size, and twin behavior.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2003년도 The 8th Asian Symposium on Precision Forging ASPF
• /
• pp.123-126
• /
• 2003

A high strength aluminum alloy bolt (A7050, T7 temper treatment) has been developed by the authors. The bolt has a small grain size in the whole area of the bolt because of the large equivalent strain followed by thermo-mechanical treatment. As the bolt made of A 7050 has a risk of stress corrosion cracking, each grain should be strengthened the grain inside than the grain boundary in order to improve the stress corrosion cracking resistance. It has been confirmed that the nano-indentation hardness at each grain inside increased with the increasing equivalent strain by thermo-mechanical treatment processing.

• 한국생산제조학회지
• /
• 제22권5호
• /
• pp.865-870
• /
• 2013

In recent years, aluminum processing has been increasing in the aerospace, vehicle, airplane industries etc., because aluminum has abundant resources and has a high specific strength. Aluminum alloys have a high coefficient of thermal expansion therefore, it is necessary to consider the temperature problem in the cutting process. The objective of this research is to investigate the machinability of a hardened aluminum alloy Al7075-T6 by using cryogenic heat treatment. The machining test is conducted by comparing the cutting force and surface roughness, corresponding to various cutting conditions of depth of cut, cutting speed, and feed rate, with those of Al7075-T0.

• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
• /
• pp.708-709
• /
• 2006

New Al-based alloys with very high ultimate tensile strength were developed in high Al concentration range of 91-95 at.% for Al-Fe-Cr-Ti-M (M: Co and Mo) systems and Al-Fe-Cr-Mo-Ti-Co system by the dispersion of nanoscale quasicrystalline particles in Al phase. The effect of adding elements, M was discussed in the viewpoint of stability of super-cooled liquid state and formation ability of quasicrystalline phase. The P/M Al-Fe-Cr-Ti-M alloys with dispersed nanoscale quasicrystalline particles exhibited ultimate tensile strength of 350MPa at 573K and 200MPa at 673K.

• Journal of Welding and Joining
• /
• 제26권5호
• /
• pp.36-42
• /
• 2008

Carbon nanotube (CNT) aluminum composite coatings were built up through kinetic spraying process. Deposition behavior of CNT aluminum composite on an aluminum 1050 alloy substrate was analyzed based on deposition mechanism of kinetic spraying. The microstructure of CNT aluminum composite coating were observed and analyzed. Also, the electrical resistivity, bond strength and micro-hardness of the CNT aluminum composite coatings were measured and compared to kinetic sprayed aluminum coatings. The CNT aluminum composite coatings have a dense structure with low porosity. Compared to kinetic sprayed aluminum coating, the CNT aluminum composite coatings present lower electrical resistivity and higher micro-hardness due to high electrical conductivity and dispersion hardening effects of CNTs.

• 한국분말재료학회지
• /
• 제29권1호
• /
• pp.28-33
• /
• 2022

Aluminum-based powders have attracted attention as key materials for 3D printing owing to their low density, high specific strength, high corrosion resistance, and formability. This study describes the effects of TiC addition on the microstructure of the A6013 alloy. The alloy powder was successfully prepared by gas atomization and further densified using an extrusion process. We have carried out energy dispersive X-ray spectrometry (EDS) and electron backscatter diffraction (EBSD) using scanning electron microscopy (SEM) in order to investigate the effect of TiC addition on the microstructure and texture evolution of the A6013 alloy. The atomized A6013-xTiC alloy powder is fine and spherical, with an initial powder size distribution of approximately 73 ㎛ which decreases to 12.5, 13.9, 10.8, and 10.0 ㎛ with increments in the amount of TiC.