Papers by Keyword: Nanoindentation

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Authors: Han Huang, Rudy Irwan, Tsunemoto Kuriyagawa
Abstract: Nanoindentation was used to study the deformation and removal mechanisms of cemented tungsten carbide. It was found that the microstructure of the material has significant influences on its mechanical properties, which determines the critical conditions for damage-free nanogrinding. The results also indicated that when material removal events occur at nanometric scale, such influences should be taken into account for gaining the full potential of nanogrinding.
Authors: Lin Zhang, Hong Wei Zhao, Zhi Chao Ma, Hu Huang, Chun Yang Geng, Zhi Chao Ma
Abstract: A series of three-dimensional molecular dynamics (MD) simulations of nanoindentation are conducted to investigate the deformation behavior and phase transformation of monocrystalline silicon with different size hemispherical diamond indenters on (010) crystal plane. The technique of coordination number (CN) is employed to elucidate the detailed mechanism of phase transformation in the monocrystalline silicon. The simulation results show that the phase transformation varies according to the different radii indenters. In the phase transformation region beneath the indenter, the crystalline structures of Si-II, Si-XIII, and amorphous phase structures are observed. In addition, the results indicate that phase transformation with large indenters is not same with the small indenter. The six-coordinated silicon phase, Si-XIII, transformed from Si-I is identified. The phases of Si-II and Si-XIII, which have the same coordinate number, are successfully extracted from the transformation region during nanoindentation and amorphous phase will emerge upon unloading.
Authors: Hsiang Chen Hsu, Wei Yao Chang
Abstract: In this paper, experimental procedures are developed to measure the tensile mechanical property of ultra thin Copper (Cu) wire (=1mil) before and after electric flame-off (EFO). Characteristics of free air ball (FAB), heat affected zone (HAZ) and as-drawn wire on 99.99% Cu wire have been carefully investigated by nanoindentation, microhardness and self-design pull test fixture, respectively. A secondary EFO technique has been conducted to reduce the strength of Cu wire and increase the bondability. The determined accurate material properties can then be applied to finite element analysis (FEA) for further reliability studies. A series of comprehensive parametric studies were conducted in this research.
Authors: Olivier Arnould, Olivier Hubert, François Hild
Authors: Yannick Champion, Sophie Nowak
Abstract: Fine grained copper was studied using the stress relaxation technique and creep testing in nano-indentation, to determine the activation volume involved in the micro-mechanism of the deformation. This material exhibits a near-perfect elasto-plastic deformation, featured by a steep work-hardening, after the elastic domain, followed by flow at a constant stress. Measurements of the activation volumes in the various domains reveal the role of the dislocations and the variation in the dislocation density in the deformation mechanism. This emphasizes the importance, in the determination of the activation volume, of the deformation domain investigated as well as the testing technique used and whether in both cases, the measurement is carried out in a transient domain or condition where variation in dislocation density occurs.
Authors: M. Rizwan Malik, Tie Lin Shi, Zi Rong Tang, Ping Peng
Abstract: A growing scientific effort is being devoted to the study of nanoscale interface aspects such as thin-film adhesion, abrasive wear and nanofriction at surfaces by using the nanoscratching technique but there remain immense challenges. In this paper, a three-dimensional (3D) model is suggested for the molecular dynamics (MD) simulation and experimental verification of nanoscratching initiated from nano-indentation, carried out using atomic force microscope (AFM) indenters on Al-film/Si-substrate systems. Hybrid potentials such as Morse and Tersoff, and embedded atom methods (EAM) are taken into account together for the first time in this MD simulation (for three scratching conditions: e.g. orientation, depth and speed, and the relationship between forces and related parameters) in order to determine the mechanisms of nanoscratching phenomena. Salient features such as nanoscratching velocity, direction and depth - as well as indenter shape- and size-dependent functions such as scratch hardness, wear and coefficient of friction - are also examined. A remarkable conclusion is that the coefficient of friction clearly depends upon the tool rake-angle and therefore increases sharply for a large negative angle.
Authors: Kun Kun Fu, Yuan Chang, Li Chang, Bai Lin Zheng
Abstract: We previously presented an energy method for predicting the bounds of fracture toughness of brittle films on a soft substrate from nanoindentation. The method is now further improved by minimizing elastic-plastic work from the measured energy during ring crack formation. Then, we applied this method to determine the limits of fracture toughness of alumina films with a thickness of 100 nm. It was found that fracture toughness of the films is in the range of 1.8-2.2 MPa.m0.5, which is consistent with those measured by the conventional method.
Authors: Hui Chao Cheng, Min Song
Abstract: Fe76.5-xSi13.5B9Cu1Alx alloys were fabricated by arc melting method plus copper mould casting technique. The effects of Al content on the microstructures and mechanical properties of the alloys were investigated. The results showed that the Al content significantly affects the microstructures and mechanical properties of the alloys. The addition of Al element into the alloy results in a variation from nanostructures to coarse grained structures. At the same time, the hardness and elastic modulus decrease with increasing the Al content.
Authors: Yan Zheng, Su Ping Cui, Ya Li Wang, Zi Ming Wang, Qian Jin Mao
Abstract: The hydration of cement is known to be a complex phenomenon. Although the broad pattern of reactions and microstructural development are known, a number of important questions remain unanswered. How to select the proper techniques is what the research people think of for now. This paper reviewed the domestic and international research progress and presented the advantages and disadvantages of these methods and the application prospects. Nuclear magnetic resonance spectroscopy (NMR), nanoindentation and electron microscopy techniques of cements were expounded in detail. Furthermore, through analyzing the results obtained by different research methods, the paper predicted the development prospect of advanced testing method of cement-based materials.
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