What does mean Nanoindentation?
Nanoindenter is basically used for securing the mechanical characteristics or properties at micro or nano-scale with the help of powerful technology known as Nanoindentation. Nanoindentation is utilized for securing the parameters of material for example hardness (H), elastic modulus (Es), viscous or plastic parameters with the help of experimental readings of penetration (h) and indenter load (P). It must be note down that forces, those are involved, are normally in the range of micro-newton or mili-newton and depth will also be in the range of nanometers. It must be recalled that very little volume of material having order of about several tens of nanometers might be determined with the only tip of nanoindenter and characteristics of material might be determined for example a very small piece of material [1-2].
History and Background:
Technique of Indentation was applied for the very first time in the early century of twentieth by Hertz in his theoretical work as a way for the determination the hardness. Then researchers such as Field and Swain in 1993 were interested to define the hardness of material, yield strength or even Young’s modulus with a new spherical indentation technique. Later, it must be note that there were various types and shapes of indenters those are applied for carrying out a variety of inspection, tests as well as the analytical definitions of hardness value by several scientists and researches as Chudoba, Oliver, Pharr, Bolshakov and Schwarzer over 10 years. In current situation, the technique of indentation was upgraded in order to avail additionally fundamental mechanical properties for example elastic modulus, hardness, resistance against scratching of various types of materials [2-3].
If we consider in case of a conventional method of indentation testing, micro or macro indentation, there will be hard tip and mechanical characteristics of this hard tip will be known; normally constructed by such a material whose hardness will be higher for example diamond; and this hard tip will be pressed into a such a work piece whose mechanical characteristics are unknown. The load (P) which is placed over the tip of indenter will be enhanced when the tip of indenter penetrates more into the work piece and very soon it will achieve user demand value:
Where H is hardness Pmax is the maximum load and A is area of Residual indentation. This technology was associated with some drawbacks. This technology utilizes varied and large tip- shape along with indenter rigs and this indenter ring doesn’t have suitable spatial resolution or we may say that the exact location of the area where indentation will be carried out is very difficult to secure accurately. Nanoindentation technology amended these micro as well as macro indentation inspections with the help of application of high spatial resolutions, very precise tip shape in order to indent the exact place by delivering real time load...