양극산화된 알루미늄과 마이크로 인덴테이션을 이용한 3 차원 마이크로-나노 하이브리드 패턴 제작

권종태(Jong Tae Kwon),신홍규(Hong Gue Shin),서영호(Young Ho Seo),김병희(Byeong Hee Kim) 대한기계학회 2007 大韓機械學會論文集A Vol.31 No.12

A simple method for the fabrication of 3D micro-nano hybrid patterns was presented. In conventional fabrication methods of the micro-nano hybrid patterns, micro-patterns were firstly fabricated and then nanopatterns were formatted on the micro-patterns. Moreover, these micro-nano hybrid patterns could be fabricated on the flat substrate. In this paper, we suggested the fabrication method of 3D micro-nano hybrid patterns using micro-indentation on the anodized aluminum substrate. Since diameter of the hemispherical nano-pattern can be controlled by electrolyte and applied voltage in the anodizing process, we can easily fabricated nano-patterns of diameter of 10㎚ to 300㎚. Nano-patterns were firstly formatted on the aluminum substrate, and then micro-patterns were fabricated by deforming the nano-patterned aluminum substrate. Hemispherical nano-patterns of diameter of 150㎚ were fabricated by anodizing process, and then micro-pyramid patterns of the side-length of 50㎛ were formatted on the nano-patterns using microindentation. Finally we successfully replicated 3D micro-nano hybrid patterns by hot-embossing process. 3D micro-nano hybrid patterns can be applied to nano-photonic device and nano-biochip application.

Estimations of work hardening exponents of engineering metals using residual indentation profiles of nano-indentation

Kim, Byung-Min,Lee, Chan-Joo,Lee, Jung-Min 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.1

This study was designed to predict work hardening exponent n of materials from AFM (atomic force microscope) observations of residual indentation impression in sharp indentations. FE simulations of nano-indentation were performed to 140 combinations to each parameter (elastic modulus E, yield stress ${\sigma}_y$, work hardening exponent n, and Poisson's ratio ${\nu}$) expressing elastic-plastic behaviors of universal engineering metals. Using the results from FE simulations and dimensional analysis, dimensionless functions were established to correlate residual indentation profiles with the work hardening exponent. This function was examined with nano-indentation, tensile test, and AFM observations after indentation for two materials (Al6061-T6 and copper).

Nano-indentation 실험과 유한요소 해석을 연계한 재료의 탄소성 물성 평가법 개발

김윤재(Y.J Kim),송태광(T.K Song),박준협(J-H Park),한준희(J-H Hahn) 한국정밀공학회 2006 한국정밀공학회 학술발표대회 논문집 Vol.2006 No.5월

Determination of elastic properties of nano-scale materials using nano-indentation tests is well established, but that of plastic properties is not yet clear. This paper presents a method to extract plastic properties from nano-indentation test, together with results from detailed elastic-plastic FE analysis. It shows that the plastic properties determined from this method are not unique, in the sense that a number of different plastic properties can give the same load-displacement response from nano-indentation test. Possible ways to overcome such problems are discussed.

나노인덴테이션과 유한요소법을 이용한 재료의 물성평가

이찬주(C.J Lee),이정민(J.M. Lee),이경수(K.S Lee),김병민(B.M. Kim) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11

Nano-indentation test is well-known method widely used to measure mechanical properties of bulk material such as elastic modulus and hardness. To evaluate the behavior of bulk material during the nano-indentation test, many theoretical models were proposed. However, because of complicated the nonlinear elastic-plastic behavior of bulk material, it is very difficult to identify the properties of bulk material using theoretical model. In this paper, the behavior of bulk materal is numerically calculated by FE analysis and through dimensionless analysis, it is identified that the relationship between the properties of bulk materials and characters of loading-unloading curve obtained by nano-indentation test. Using this relationship, the properties of bulk material were extracted from nano-indentation curve. To verify reliability of properties compared loading-unloading curves obtained by nano-indentation test and FE analysis.

나노 인덴테이션을 이용한 산화알루미늄(AAO, Anodic Aluminum Oxide)구조물의 물성치에 대한 연구

고성현(Seong Hyun Ko),이대웅(Dae Woong Lee),지상은(Sang Eun Jee),박현철(Hyun Chul Park),이건홍(Kun Hong Lee),황운봉(Woonbong Hwang) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.4

Porous anodic alumina has been used widely for corrosion protection of aluminum surfaces or as dielectric material in micro-electronics applications. It exhibits a homogeneous morphology of parallel pores which can easily be controlled between 10 and 400nm. It has been applied as a template for fabrication of the nanometerscale composite. In this study, mechanical properties of the AAO structures are measured by the nano indentation method. Nano indentation technique is one of the most effective method to measure the mechanical properties of nano-structures. Basically, hardness and elastic modulus can be obtained by the nano-indentation. Using the nano-indentation method, we investigated the mechanical properties of the AAO structure with different size of nano-holes. In results, we find the hole effect that changes the mechanical properties as size of nano hole.

나노 압입곡선의 탄성해석과 pile-up 거동 예측을 통한 (100) 텅스텐 단결정의 탄성계수 및 경도 평가

이윤희,권동일 대한금속재료학회 2002 대한금속·재료학회지 Vol.41 No.2

Hardness and elastic modulus calculated from the Oliver and Pharr's indentation curve analysis are overestimated for ductile metals comparing with the values measured from the direct observation of residual indentation impression. A dominant cause of the phenomenon is material pile-up around contact. However it is very difficult to consider the pile-up in analyzing the indentation curve without observing the residual indentation mark. Therefore, we propose an indirect analysis of the pile-up effect by estimating the elastic modulus independently based on the Hertzian contact theory. Pile-up corrected contact area is predicted from the conventional elastic recovery equation by inserting the pre-determined elastic modulus. The proposed analysis is applied to the nano-indentation tests on (100) tungsten single crystal and produced a reasonable hardness comparing with the direct observation result through an atomic force microscope.

Nano-Mechanical and Tribological Characteristics of Ultra-Thin Amorphous Carbon Film Investigated by AFM

Chung, Koo-Hyun,Lee, Jae-Won,Kim, Dae-Eun The Korean Society of Mechanical Engineers 2004 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.18 No.10

The mechanical as well as tribological characteristics of coating films as thin as a few nm become more crucial as applications in micro-systems grow. Especially, the amorphous carbon film has a potential to be used as a protective layer for micro-systems. In this work, quantitative evaluation of nano-indentation, scratching, and wear tests were performed on the 7nm thick amorphous carbon film using an Atomic Force Microscope (AFM). It was shown that AFM-based nano-indentation using a diamond coated tip can be feasibly utilized for mechanical characterization of ultra-thin films. Also, it was found that the critical load where the failure of the carbon film occurred was about 18${\mu}$N by the ramp load scratch test. Finally, the wear experimental results showed that the quantitative wear rate of the carbon film ranged 10$\^$-9/~10$\^$-8/ ㎣ /N cycle. These experimental methods can be effectively utilized for a better understanding the mechanical and tribological characteristics at the nano-scale.

알루미나에 YSZ가 나노코팅된 층상형 시스템의 인덴테이션 특성평가

김상겸,김태우,김철,신태호,한인섭,우상국,이기성,Kim, Sang-Kyum,Kim, Tae-Woo,Kim, Chul,Shin, Tae-Ho,Han, In-Sub,Woo, Sang-Kuk,Lee, Kee-Sung 한국세라믹학회 2005 한국세라믹학회지 Vol.42 No.1

전자 범 물리적 증착법(Electron Beam Physical Vaper Deposition, EB-PVD)으로 알루미나 상용기판 위에 나노 크기의 YSZ입자를 포함하고 있는 층을 코팅하여 층상형 시스템을 제조하였으며, 이때 기판층의 온도를 600, 700, $800^{circ}C$로 변화시켜 증착되는 YSZ층이 서로 다른 미세구조가 형성되도록 제어하여, 코팅층 미세구조의 변화에 따른 인덴데이션 거동을 고찰하였다 인덴테이션 거동으로는 비커스 인덴테이션과 헤르찌안 인덴테이션으로 피라미드형 압자 혹은 초경 구를 압입하였으며 압입 하중 및 코링층 구조에 따른 경도와 인덴테이션 응력-변형률 곡선을 구하였고, 미세구조와 하중의 증가에 따른 손상 및 파괴거동을 고찰하였다. 기판층의 온도가 향상됨에 따라 증착된 입자의 크기가 보다 증가하고 각진 입자가 형성됨을 알 수 있었고, 서로 다른 미세구조가 인덴테이션 거동에 영향을 주어, $800^{circ}C$에서 증착된 YSZ/A12달 구조가 상대적으로 우수한 특성을 나타내었다. YSZ layer containing nano-sized particles has been deposited on the commercial A1203 substrate by Electron Beam Physical Vapor Deposition (EB-PVD). The role of coating rnjcrostructures of YSZ to indentation damage is studied. The different coating microsouctures are prepared by varying the substrate temperatures from $600^{circ}C$ to $800^{circ}C$ during the deposition. Microhardness test and Hertzian indentation are conducted on the $YSZ/Al_{2}O_{3}$ layered systems. The damage and flilure behaviors have been investigated according to the effect of microstructures and indentation loads. With increasing the substrate temperature during EB-PVD, the overall grain sizes are coarser and more faceted, which microsoucture ultimately influences on the indentation behavior, thus, YSZ/Al_{2}O_{3}$ layered system prepared at the substrate temperature of $800^{circ}C$ shows relatively higher damage tolerance.

Mechanical properties of top neck mollusks shell nano composite in different environmental conditions

Masir, Amin Nouroozi,Darvizeh, Abolfazl,Zajkani, Asghar Techno-Press 2018 Advances in materials research Vol.7 No.3

The mechanism of biological materials structure is very complex and has optimal properties compared to engineering materials. Top Neck mollusks shells, as an example of biological materials, have hierarchical structure, which 95 percent of its structure is Aragonite and 5 percent organic materials. This article detected mechanical properties of the Top Neck mollusks shell as a Nano composite using Nano-indentation method in different situations. Research findings indicate that mechanical properties of the Top Neck mollusks shell including elastic modulus and hardness are higher than a fresh one preserved in -50 centigrade and also a Top Neck mollusks shell preserved in environmental conditions. Nano-indentation test results are so close in range, overall, that hardness degree is 3900 to 5200 MPa and elastic modulus is 70 to 85 GPa.

Nano and Neutron Science Applications for Geomechanics

Dayakar Penumadu,Amal K. Dutta,Xin Luo,Kenneth G. Thomas 대한토목학회 2009 KSCE Journal of Civil Engineering Vol.13 No.4

Recent advances in experimental characterization techniques offer unique opportunities to evaluate mechanical properties of geomaterials. In this paper, authors introduce two such techniques that have significant potential to impact geomechanics community. The technique of using Instrumented indentation testing using nano-indenter to evaluate hardness and modulus of individual sand particles is introduced. Use of the measured data from nanoindenter on individual sand grain in modelling its assembly using numerical methods such as the discrete element method (for example PFC-2D) is addressed. Modulus for two silica sands with varying particle shape is presented for the depth of indentation in the range of 100 to 1000 nanometers. Use of neutron science for solving relevant problems to geotechnical engineering is also described in this paper. Neutrons are subatomic particles with no electric charge having duality and interacts with atomic nuclei, while X-ray interacts with electrons. Neutrons thus have significantly higher penetration power for most geo-materials when compared to X-rays and are sensitive to hydrogen. Use of neutrons for solving a new class of problems including non-destructive evaluation of strain at particle level while the assemblage is subjected to target stress conditions, and imaging applications including flow through partially saturated porous medium are presented. Recent advances in experimental characterization techniques offer unique opportunities to evaluate mechanical properties of geomaterials. In this paper, authors introduce two such techniques that have significant potential to impact geomechanics community. The technique of using Instrumented indentation testing using nano-indenter to evaluate hardness and modulus of individual sand particles is introduced. Use of the measured data from nanoindenter on individual sand grain in modelling its assembly using numerical methods such as the discrete element method (for example PFC-2D) is addressed. Modulus for two silica sands with varying particle shape is presented for the depth of indentation in the range of 100 to 1000 nanometers. Use of neutron science for solving relevant problems to geotechnical engineering is also described in this paper. Neutrons are subatomic particles with no electric charge having duality and interacts with atomic nuclei, while X-ray interacts with electrons. Neutrons thus have significantly higher penetration power for most geo-materials when compared to X-rays and are sensitive to hydrogen. Use of neutrons for solving a new class of problems including non-destructive evaluation of strain at particle level while the assemblage is subjected to target stress conditions, and imaging applications including flow through partially saturated porous medium are presented.