Conditions of applying Oliver–Pharr method to the nanoindentation of particles in composites
نویسندگان
چکیده
The indentation test is a popular experimental method to measure a material’s mechanical properties such as elastic modulus and hardness, and the Oliver–Pharr method is commonly used in commercial indentation instruments to obtain these two quantities. To apply the Oliver–Pharr method correctly in all of these cases, it is essential to know the limitations of this method. The present study focuses on the applicability of the Oliver–Pharr method to measure the mechanical properties of particles in composites. The finite element method is used to undertake virtual indentation tests on a particle embedded in a matrix. In our numerical studies, the indentation ‘‘pile-up’’ phenomenon is generally observed in our numerical case studies, which indicates that the contact area used for predicting the elastic modulus should be measured directly, not be estimated from the indentation curve. The Oliver–Pharr method based on the real contact area is applied to estimate the elastic modulus of the particles by using the indentation curve from the numerical simulation, with the estimated elastic modulus being compared with the input value. Applying the real contact area value (not the one predicted from the indentation curve) we show that the Oliver–Pharr method can still be applied to measure the elastic modulus of the particle with sufficient accuracy if the indentation depth is smaller than the particle-dominated depth, a value defined in this work. The influences of the matrix and particle properties on the particle-dominated depth are studied using a dimensional analysis and parametric study. Our results provide guidelines to allow the practical application of the Oliver–Pharr method to measure the elastic modulus of particles in composites. This could be particularly important where particles are formed in situ in a matrix (as opposed to being preformed and subsequently incorporated in a matrix), or when the modulus of individual performed particles is required such as for subsequent modelling, but the modulus of individual material particles (or its material) cannot readily be determined. 2012 Elsevier Ltd. All rights reserved.
منابع مشابه
Some issues on nanoindentation method to measure the elastic modulus of particles in composites
The application of the indentation method to measure the elastic modulus of particles embedded in a composite is theoretically investigated in this paper by finite element simulation. The Oliver–Pharr method, which is widely used in commercial nanoindentation instruments, is used to probe the elastic modulus of the particle from the simulated indentation curve. The predicted elastic modulus is ...
متن کاملStuttgart Mechanics of Soft Polymer Indentation
3 Julia Deuschle Mechanics of Soft Polymer Indentation 189 pages, 67 figures, 8 tables Abstract Nanoindentation has become a fast and reliable technique for the mechanical characterization of engineering materials. The applicability of this technique to small or confined volumes and the subμN and subnm resolution of the instruments are unique features in the field of mechanical testing and make...
متن کاملAn investigation on Mechanical Properties of Apatite-Wollastonite-Diopside Glass-Ceramics Composites
Apatite-wollastonite (A-W)-phlogopite glass-ceramic is considered to be difficult to resorb, but often, it has been incorporated in particulate form to create new bioactive composites for potential maxillofacial applications. With various compositions, the present work has attempted to prepare apatite-wollastonite (A-W)-phlogopite glass ceramic composites, by applying sintering. Here, three-poi...
متن کاملتولید پودر کامپوزیتی آلومینیم 2024-گرافیت با روش از هم گسیختگی مذاب به کمک فاز جامد
In this study, Aluminium2024- Graphite composites containing 5, 10, 15 and 20 weight percent of graphite were produced by solid assisted melt disintegration (SAMD) technique which resulted in production of Al/Gr powder mixtures which subsequently consolidated and sintered for preparation of Al/Gr composites. In this technique, powder mixture was prepared by addition of flake graphite (mean diam...
متن کاملThe Effect of Aging on Nano-Hardness and Modulus of Elasticity of Four Types of Composites: An in-vitro Study
Introduction: Resin composites are an important part of restorative treatment in modern dentistry. There are many trademarks available in Iran market and physico-chemical properties of many of these resin composites are not evaluated yet. This study was carried out to evaluate the physico-chemical properties of four available resin composites and also to assess the effect of aging on their prop...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2012