A Methodology for the Calibration of Spherical Indenters

1999 ◽  
Vol 594 ◽  
Author(s):  
J. G. Swadener ◽  
G. M. Pharr
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Surface Roughness ◽  
Confocal Microscopy ◽  
Testing Machine ◽  
Ceramic Materials ◽  
Spherical Indentation ◽  
Depth Measurement ◽  
Elastic Range ◽  
Elastic Responses

AbstractSpherical indentation with continuous load and depth measurement is a useful technique for characterizing thin film mechanical properties. With this technique, the initial loading is in the elastic range. Therefore the elastic-plastic transition can be observed. However, the calibration of spherical indenters presents special problems. First, the radius of the indenter at the point of contact must be determined, and any deviation from a spherical radius must be evaluated. The shape of the indenter also causes mounting difficulties that can create a relatively large and nonlinear compliance in the testing machine. The calibration of spherical indenters is further complicated, because asperities on the indenter and surface roughness add to the uncertainty in locating the surface of the sample. In addition, spherical indenters are generally made of anisotropic single crystals, and the calculation of their elastic responses must include this anisotropy. To address these issues, a methodology has been developed for the calibration of spherical indenters, whereby indentation experiments are conducted on multiple ceramic materials in the elastic range. The method was used to determine the local radius of synthetic sapphire spherical indenters. The accuracy of this measurement was verified using confocal microscopy. The method was successfully applied to an indenter with a nonlinear machine compliance. Further results involving indentation in the plastic regime are also presented.

STUDY OF THE PHYSICOMECHANICAL PROPERTIES OF 08Kh18N10T STAINLESS STEEL PIPES EXPOSED TO ULTRASOUND UPON DRAWING

2019 ◽  
Vol 85 (5) ◽  
pp. 33-37
Author(s):  
S, M. Nebogov ◽  
S. A. Evsyukov ◽  
S. N. Svidunovich ◽  
Y. Y. Maltsev ◽  
A. A. Sobranin
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Testing Machine ◽  
Physical And Mechanical Properties ◽  
Physicomechanical Properties ◽  
Ultra Sound ◽  
08Kh18n10t Steel ◽  
Steel Pipes

The drawing of pipes exposed to ultrasonic vibrations of radial type and their effect on the physical and mechanical properties of the pipe, as well as on the surface quality is studied. The ultrasonic unit with radial vibrations tested under production conditions is used to study the effect of ultrasound on the residual stresses present after drawing, surface roughness, as well as on the physical and mechanical properties and microdefects of 08Kh18N10T steel pipes. Defects and residual stresses before and after drawing under the effect of ultrasound were analyzed by the method of magnetic memory, using the stress concentration meter TSC-4M-16 with an eight-channel scanning device with four two-component sensors (Type 15). It is shown that the residual stresses decreased by more than two times under the effect of ultrasound. The surface roughness after drawing with ultrasound ranged within Ra = 0.087 - 0.092 µm. The physicomechanical properties were studied in tensile tests on an Instron tensile testing machine (SATEC Series). The yield stress qt was 551, the tensile strength qin — 672 MPa. It is shown that the effect of ultra-sound upon drawing pipes made of 08X18H10T stainless steel enhance their quality through reduction of the surface roughness and improved physicomechanical properties.

Evaluation of Young's Modulus and Yield Strength of Thin Film Structural Material Using Nanoindentation Technique

1999 ◽  
Vol 562 ◽  
Author(s):  
Dongil Son ◽  
Yun-Hee Lee ◽  
Jeong-Hoon Ahn ◽  
Dongil Kwon
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Yield Strength ◽  
Film Thickness ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Surface Condition ◽  
Sensors And Actuators ◽  
Elastic Range ◽  
Silicon Bulk

ABSTRACTAluminum films have wide applications in micromechanical devices such as micro sensors and actuators. Therefore, their mechanical properties are very important for reliability evaluation. However, there is no standardized method to evaluate the mechanical properties of the materials used in MEMS(microelectromechanical system) devices since the measured mechanical properties are influenced by many factors such as the surface condition of materials, intrinsic limit of the measurement device, etc. Hence, it was intended to evaluate the mechanical properties of thin film, which is important in its mechanical operation. Because MEMS devices are usually operated in the elastic range, Young's modulus and yield strength were evaluated by using a microcantilever beam technique. First, A1 cantilever beams were fabricated using the silicon bulk micromachining technology to have various film thicknesses. The load-displacement curves during beam bending by nanoindentation method were then obtained. The linear relationship of the curve in elastic range was utilized in deriving Young's modulus of the A1 film, which gave reproducible results regardless of film thickness. In the high load range, the deviation from the linear relation was detected, so that yield strength of A1 film could be evaluated. It was found that the yield strength increases with decreasing film thickness. By applying the misfit dislocation theory and the Hall-Petch relationship, the theoretical estimation could predict the trend of yield strength.

Mechanical Properties of Poly 3C-SiC Thin Films According to Carrier Gas (H2) Concentration

2008 ◽  
Vol 600-603 ◽  
pp. 867-870
Author(s):  
Gwiy Sang Chung ◽  
Ki Bong Han
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Mechanical Properties ◽  
Surface Roughness ◽  
Atomic Force Microscope ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Carrier Gas ◽  
Nano Indentation ◽  
Atomic Force

This paper presents the mechanical properties of 3C-SiC thin film according to 0, 7, and 10 % carrier gas (H2) concentrations using Nano-Indentation. When carrier gas (H2) concentration was 10 %, it has been proved that the mechanical properties, Young’s Modulus and Hardness, of 3C-SiC are the best of them. In the case of 10 % carrier gas (H2) concentration, Young’s Modulus and Hardness were obtained as 367 GPa and 36 GPa, respectively. When the surface roughness according to carrier gas (H2) concentrations was investigated by AFM (atomic force microscope), when carrier gas (H2) concentration was 10 %, the roughness of 3C-SiC thin was 9.92 nm, which is also the best of them. Therefore, in order to apply poly 3C-SiC thin films to MEMS applications, carrier gas (H2) concentration’s rate should increase to obtain better mechanical properties and surface roughness.

The Application of Grinding of Ceramic Materials

2018 ◽  
Vol 919 ◽  
pp. 215-221
Author(s):  
Dana Stancekova ◽  
Jana Petrů ◽  
Jaroslava Svobodova ◽  
Izabela Miturska ◽  
Sarka Molotova
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Production Process ◽  
Cutting Forces ◽  
High Hardness ◽  
Ceramic Materials ◽  
Cutting Conditions ◽  
Whole Process ◽  
Technical Ceramics ◽  
Roughness Evaluation

An application of hard engineering materials depends especially on their specific properties, included mechanical properties and their machinability. Technical ceramics belongs to such materials. Nowadays, due to its properties, it is a process of grinding that is applied in machining. Because the technical ceramics has high hardness and brittleness it is important to pay attention to the whole process of machining. In this case of the grinding, there is need to pay attention to the process from disc engagement to grind off the desired layer. The paper deals with an implementation of grinding of ceramic materials in context of determining of elements of cutting forces and the surface roughness evaluation. These are important aspects for determining the suitability of the cutting conditions and the possibility of their use in the production process.

Determination of Young’s Modulus and Poisson’s Ratio of Coatings With Non-Destructive Indentation

2005 ◽  
Author(s):  
S. Jordan Liu ◽  
Q. Jane Wang
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Poisson's Ratio ◽  
Spherical Indentation ◽  
Engineering Practice ◽  
Substrate Effect ◽  
Non Destructive

Coatings are now extensively used in engineering practice to modify the surfaces of mechanical components for enhanced load-bearing ability, lubricity, and service endurance. Designing thin-film coatings to meet particular engineering needs requires the knowledge of accurate mechanical properties of the coatings. Young’s modulus and Poisson’s ratio are two basic mechanical properties of materials, which should be conveniently measured. However, the measurement of Young’s modulus of a thin film is hindered by the inevitable substrate effect when the conventional methods for a bulk material are used to obtain so called “reduced modulus”. This paper presents a direct and non-destructive method for the measurement of Young’s modulus and Poisson’s ratio of a thin-film coating and its substrate, based on the extended-Hertz theory developed for coated bodies in contact. The theory is used to analyze load-displacement data from a spherical indentation in the elastic range, where the substrate effect is intrinsically modeled. Two sets of validation experiments are shown for coatings of a few microns thick. This new method does not need any assumption on pressure distribution and Poisson’s ratio and can be easily incorporated into current indentation analysis systems.

Microstructural and fractographic characterization of B4C-Al cermets tested under dynamic and static loading

1989 ◽  
Vol 47 ◽  
pp. 562-563
Author(s):  
Gyeung Ho Kim ◽  
Mehmet Sarikaya ◽  
D. L. Milius ◽  
I. A. Aksay
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Static Loading ◽  
Carbon Deposition ◽  
Full Density ◽  
Unique Combination ◽  
Strong Component ◽  
Reaction Products

Cermets are designed to optimize the mechanical properties of ceramics (hard and strong component) and metals (ductile and tough component) into one system. However, the processing of such systems is a problem in obtaining fully dense composite without deleterious reaction products. In the lightweight (2.65 g/cc) B4C-Al cermet, many of the processing problems have been circumvented. It is now possible to process fully dense B4C-Al cermet with tailored microstructures and achieve unique combination of mechanical properties (fracture strength of over 600 MPa and fracture toughness of 12 MPa-m1/2). In this paper, microstructure and fractography of B4C-Al cermets, tested under dynamic and static loading conditions, are described.The cermet is prepared by infiltration of Al at 1150°C into partially sintered B4C compact under vacuum to full density. Fracture surface replicas were prepared by using cellulose acetate and thin-film carbon deposition. Samples were observed with a Philips 3000 at 100 kV.

INFLUENCE THE QUENCHING AND TEMPERING ON THE MICROSTRUCTURE, MECHANICAL PROPERTIES AND SURFACE ROUGHNESS, OF MEDIUM CARBON STEEL

2018 ◽  
Vol 18 (1) ◽  
pp. 125-135
Author(s):  
Sattar H A Alfatlawi
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Surface Roughness ◽  
Carbon Steel ◽  
Cold Water ◽  
Medium Carbon Steel ◽  
Medium Carbon ◽  
Heating And Cooling ◽  
Treatment Processes ◽  
Quenching And Tempering

One of ways to improve properties of materials without changing the product shape toobtain the desired engineering applications is heating and cooling under effect of controlledsequence of heat treatment. The main aim of this study was to investigate the effect ofheating and cooling on the surface roughness, microstructure and some selected propertiessuch as the hardness and impact strength of Medium Carbon Steel which treated at differenttypes of heat treatment processes. Heat treatment achieved in this work was respectively,heating, quenching and tempering. The specimens were heated to 850°C and left for 45minutes inside the furnace as a holding time at that temperature, then quenching process wasperformed in four types of quenching media (still air, cold water (2°C), oil and polymersolution), respectively. Thereafter, the samples were tempered at 200°C, 400°C, and 600°Cwith one hour as a soaking time for each temperature, then were all cooled by still air. Whenthe heat treatment process was completed, the surface roughness, hardness, impact strengthand microstructure tests were performed. The results showed a change and clearimprovement of surface roughness, mechanical properties and microstructure afterquenching was achieved, as well as the change that took place due to the increasingtoughness and ductility by reducing of brittleness of samples.

Friction Force and Stresses Analysis for Contact of Assembled Details

2006 ◽  
Vol 113 ◽  
pp. 334-338
Author(s):  
Z. Dreija ◽  
O. Liniņš ◽  
Fr. Sudnieks ◽  
N. Mozga
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Plastic Deformation ◽  
Friction Force ◽  
Sliding Friction ◽  
Friction Model ◽  
Contact Interface ◽  
Finite Element Program ◽  
Elastic Plastic ◽  
Element Program

The present work deals with the computation of surface stresses and deformation in the presence of friction. The evaluation of the elastic-plastic contact is analyzed revealing three distinct stages that range from fully elastic through elastic-plastic to fully plastic contact interface. Several factors of sliding friction model are discussed: surface roughness, mechanical properties and contact load and areas that have strong effect on the friction force. The critical interference that marks the transition from elastic to elastic- plastic and plastic deformation is found out and its connection with plasticity index. A finite element program for determination contact analysis of the assembled details and due to details of deformation that arose a normal and tangencial stress is used.

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