• 한국레이저가공학회지
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• 제17권2호
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• pp.1-4
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• 2014

With the PEO(Plasma electrolytic oxidation) surface treatment, the oxide film of aluminum alloy is growing in a short time. The reflectance measurement to find the oxygen atoms in the oxide could be investigated. In order to form a thicker oxide film, the PEO surface treatment should be uniformly controlled in processing time.

• 소성∙가공
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• 제20권2호
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• pp.167-172
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• 2011

The numerical simulation of the Forming Limit Diagram(FLD) test was carried out to calculate the limiting dome height(LDH: ISO12004-2) for aluminum alloy sheet Al6061-T6. The finite element analysis was used as an effective method for evaluating formability and diagnosing possible production problems in sheet stamping operations. To predict fracture during the stamping process, several failure models such as Cockcroft-Latham, Rice-Tracey, Brozzo and ESI-Wilkins-Kamoulakos(EWK) criteria were applied. The predicted results were discussed and compared with the experiments for Al6061-T6.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2011년도 춘계학술대회 및 Fine pattern PCB 표면 처리 기술 워크샵
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• pp.207-207
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• 2011

The numerical simulation of the Forming Limit Diagram(FLD) test was carried out to calculate the limiting dome height(LDH: ISO12004-2) for aluminum alloy sheet Al6061-T6. The finite element analysis was used as an effective method for evaluating formability and diagnosing possible production problems in sheet stamping operations. To predict fracture during the stamping process, several failure models such as Cockcroft-Latham, Rice-Tracey, Brozzo and ESI-Wilkins-Kamoulakos(EWK) criteria were applied. The predicted results were discussed and compared with the experiments for Al6061-T6.

• 대한기계학회논문집A
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• 제35권10호
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• pp.1145-1153
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• 2011

본 연구의 목적은 극저온 열처리를 통해 Al6061 의 열처리 잔류응력을 제거하는 것이다. 이를 위해 유한요소해석을 이용하여 열처리 잔류응력을 예측하였으며, 열처리 조건에 따른 각 단계별 대류 열전달계수를 T6 와 극저온 열처리 실험을 수행하여 결정하였다. 예측된 잔류응력 결과는 X 선회절법(XRD)으로 측정된 잔류응력 결과와 비교하여 유한요소해석 결과의 타당성을 확인하였다. 또한 T6 와 극저온 열처리에 대해 각각 전기 전도도와 경도를 측정하여 기계적 특성을 평가하고 TEM 관찰과 XRD 회절 분석을 통해 석출물의 크기 및 성분을 파악하였다. 이를 통해 Al6061 의 T6 열처리와 비교하여 극저온 열처리를 적용함에 따른 잔류응력, 기계적 특성 및 미세조직변화를 조사하였다.

• 한국주조공학회지
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• 제37권2호
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• pp.38-44
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• 2017

Given that the conventional extrusion of high-strength Al alloys such as 7075 aluminum alloys is difficult due to their very low extrudability as compared to that of 6061 aluminum alloys, thixo-extrusion can be used to obtain a high-strength material easily at a lower extrusion pressure as compared to conventional extrusion. In this study, hot- and thixo-extruded 7075 aluminum alloys are prepared by a vertical forward extrusion process and their microstructures, hardness levels, and compressive properties are investigated. Hot-extruded alloy bars are assessed to obtain a microstructure elongated in the extrusion direction, whereas with thixo-extruded alloy bars, it was possible to obtain a microstructure having fine and equiaxed grains by dynamic recrystallization. The resulting isotropy and improved formability at the hot deformation temperature of the thixo-extruded alloy were attributed to the fine and equiaxed grains formed by the thixo-extrusion process.

• Composites Research
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• 제12권5호
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• pp.1-11
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• 1999

본 연구는 단섬유보강 금속복합재료의 피로 및 주기적 거동에 관한 연구로서, 가압용침법을 이용하여 제조된 Al6061과 이를 기지금속으로 사용한 단섬유보강 Al/$Al_2O_3$-15% 복합재료의 주기적변형(cyclic deformation)과 피로거동(fatigue behavior)에 대해서 실험적으로 고찰하였다. Al/$Al_2O_3$ 복합재로의 피로강도는 210MPa로 나타났고 기지금속은 170MPa로 나타났다. 영구소성변형에 의한 합변위는 피로수명 초기 5%이내에서 대부분 발생하며 파단시의 합변위는 복합재료와 기지금속 모두 축적된 소성변형으로 인하여 인장시험에서의 연신율에 비해 작은 값을 가진다. 금속복합재료의 주기적 변위는 보강재가 전위 전파의 저지역할을 함으로써 기지금속에 비하여 다소 감소하는 것으로 나타났다. 파면관찰결과 기지금속의 경우 금속복합재료에 비해 전체 시험편 단면에서 넓은 영역에서 균열전파 형태를 관찰할 수 있었으며, 또한 금속복합재료의 파면에서는 연속적인 피로하중에 의한 기지금속과 보강재간의 분리(debonding)등의 결과로 보강재가 뽑혀나간 흔적이 관찰되고 있다.

• 한국분말재료학회지
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• 제30권3호
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• pp.255-261
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• 2023

Aluminum alloys are widely utilized in diverse industries, such as automobiles, aerospace, and architecture, owing to their high specific strength and resistance to oxidation. However, to meet the increasing demands of the industry, it is necessary to design new aluminum alloys with excellent properties. Thus, a new method is required to efficiently test additively manufactured aluminum alloys with various compositions within a short period during the alloy design process. In this study, a combinatory approach using a direct energy deposition system for metal 3D printing process with a dual feeder was employed. Two types of aluminum alloy powders, namely Al6061 and Al-12Cu, were utilized for the combinatory test conducted through 3D printing. Twelve types of Al-Si-Cu-Mg alloys were manufactured during this combinatory test, and the relationship between their microstructures and properties was investigated.

• Journal of Welding and Joining
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• 제34권3호
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• pp.23-30
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• 2016

This paper discusses the optimization of friction stir spot welding (FSSW) process parameters for joining Aluminum alloy (AA6061-T6) with Magnesium alloy (AZ31B) sheets. Prior to optimization an empirical relationship was developed to predict the Tensile Shear Fracture Load (TSFL) incorporating the four most important FSSW parameters, i.e., tool rotational speed, plunge rate, dwell time and tool diameter ratio, using response surface methodology (RSM). The experiments were conducted based on four factor, five levels central composite rotatable design (CCD) matrix. The maximum TSFL obtained was 3.61kN, with the tool rotation of 1000 rpm, plunge rate of 16 mm/min, dwell time of 5 sec and tool diameter ratio of 2.5.

• 한국정밀공학회지
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• 제13권5호
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• pp.122-130
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• 1996

In this study, machinability of some aluminum-magnesium alloy are experimentally investigated using polycrystalline diamond tool with turning, and evaluated some independent cutting variables affected micrometal cutting characteristics as cutting force, specific cutting resistance, shear angles. To know the effect of cutting parameters of single point diamond machining, experiments were performed to measure cutting forces for high speed turning of aluminum alloy 6061-T6, SM45C and FC20 with poly- crystalline diamond and coated cemented carbide tool. Independent cutting variables were changed to a variety of cutting speed, feed rate, rake angles, material properties of workpiece and tool. Futhermore. Some useful informations are obtained in this study can guide micro metal cutting of aluminum alloy with diamond tool.

• 비파괴검사학회지
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• 제32권1호
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• pp.20-26
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• 2012

본 연구의 목적은 비접촉식 레이저 여기 표면파의 비선형성 계측을 통하여 소성 변형된 알루미늄 합금의 소성변형을 평가하고자 하는 데 있다. 슬릿마스크와 고출력 펄스 레이저를 통한 선배열 레이저빔을 이용하여 협대역의 표면파를 발생 시켰으며, 표면파의 음향 비선형 특성을 이용하기 위하여 슬릿 마스크의 열림 폭과 간격을 변화시킴으로써 레이저 여기 표면파의 주파수 특성을 제어하였다. 스트로크 제어를 통한 인장시험을 통하여 단계별 인장 소성변형 정도를 달리하는 시험편을 제작하였다. 실험결과 인장 소성 변형율이 커짐에 따라 음향 비선형 파라미터는 증가하였으며, 경도 및 EBSD 측정결과 손상의 정도와 매우 밀접한 관계를 보였다. 결과적으로 본 연구에서의 레이저 여기 표면파의 비선형 평가기법은 알루미늄 합금의 소성변형 평가에 매우 유용할 것으로 판단된다.