Loubet et al. [35] proposed a flat-ended punch model to estimate the stiffness of the specimen. Later, Hay et al. [36] showed that since the boundary conditions used in elastic contact models allow for inward displacement of the surface, a shape factor of the indenter, β, is introduced: (12) where S is the stiffness of the test material, obtained from the initial unloading slope at maximum load and maximum depth; A is the projected
contact area of the indenter at maximum loading condition; and E r is the reduced modulus or combined modulus. The value of shape factor β for a cylindrical indenter is 1 [37]. E r represents a balance between Young’s modulus of the sample, E s, selleck chemicals and that of the indenter, E i, because both the sample and the indenter experience elastic deformation during the indentation process: (13) where E and v are Young’s modulus and Poisson’s ratio for the specimen, respectively, and E 0 MM-102 concentration and v 0 are the same parameters for the diamond indenter, respectively. The copper property used in this study’s calculation is v = 0.3 [38]. Since the diamond indenter in this study is assumed to be perfectly rigid with
E 0 = ∞, Equation 13 can be simplified as (14) Combining it with Equation 12, we obtain (15) In the end, the calculated Young’s modulus values of copper are 194.1 and 255.3 GPa for wet indentation (case 1) and dry indentation (case 2), respectively. Young’s modulus measured by dry indentation is significantly greater than that measured by wet indentation. This is attributed to its higher stiffness as observed during the initial unloading period from the load-unload curve, as shown in Figure 7. Figure 7 Load-unload curve for wet and dry indentations (cases 1 and 2). Furthermore, regarding the hardness and Young’s modulus measurements of the copper material, a comparison between this study and the {Selleck Anti-cancer Compound Library|Selleck Anticancer Compound Library|Selleck Anti-cancer Compound Library|Selleck Anticancer Compound Library|Selleckchem Anti-cancer Compound Library|Selleckchem Anticancer Compound Library|Selleckchem Anti-cancer Compound Library|Selleckchem Anticancer Compound Library|Anti-cancer Compound Library|Anticancer Compound Library|Anti-cancer Compound Library|Anticancer Compound Library|Anti-cancer Compound Library|Anticancer Compound Library|Anti-cancer Compound Library|Anticancer Compound Library|Anti-cancer Compound Library|Anticancer Compound Library|Anti-cancer Compound Library|Anticancer Compound Library|Anti-cancer Compound Library|Anticancer Compound Library|Anti-cancer Compound Library|Anticancer Compound Library|Anti-cancer Compound Library|Anticancer Compound Library|buy Anti-cancer Compound Library|Anti-cancer Compound Library ic50|Anti-cancer Compound Library price|Anti-cancer Compound Library cost|Anti-cancer Compound Library solubility dmso|Anti-cancer Compound Library purchase|Anti-cancer Compound Library manufacturer|Anti-cancer Compound Library research buy|Anti-cancer Compound Library order|Anti-cancer Compound Library mouse|Anti-cancer Compound Library chemical structure|Anti-cancer Compound Library mw|Anti-cancer Compound Library molecular weight|Anti-cancer Compound Library datasheet|Anti-cancer Compound Library supplier|Anti-cancer Compound Library in vitro|Anti-cancer Compound Library cell line|Anti-cancer Compound Library concentration|Anti-cancer Compound Library nmr|Anti-cancer Compound Library in vivo|Anti-cancer Compound Library clinical trial|Anti-cancer Compound Library cell assay|Anti-cancer Compound Library screening|Anti-cancer Compound Library high throughput|buy Anticancer Compound Library|Anticancer Compound Library ic50|Anticancer Compound Library price|Anticancer Compound Library cost|Anticancer Compound Library solubility dmso|Anticancer Compound Library purchase|Anticancer Compound Library manufacturer|Anticancer Compound Library research buy|Anticancer Compound Library order|Anticancer Compound Library chemical structure|Anticancer Compound Library datasheet|Anticancer Compound Library supplier|Anticancer Compound Library in vitro|Anticancer Compound Library cell line|Anticancer Compound Library concentration|Anticancer Compound Library clinical trial|Anticancer Compound Library cell assay|Anticancer Compound Library screening|Anticancer Compound Library high throughput|Anti-cancer Compound high throughput screening| literature is made in Table 5. The results of
MD simulation in this study are compared with the results obtained in other MD simulation studies of dry nano-indentation, as well as the experimental measurements obtained at micro- and nano-scale in the literature. From the table, the hardness and Young’s modulus values obtained in our study are overall consistent with other Racecadotril MD simulation studies in the literature. However, all the MD simulation studies produce higher values of hardness and Young’s modulus than the existing experiment studies. The large discrepancy is due to the scale differences between MD simulation and experiment. The simulation assumes a perfect structure of single-crystalline copper lattice at the nano/atomistic scale, which is smaller than any existing nano-indentation experiments. Within the regular high-purity copper, many defects exist such as grain boundaries and precipitates at the grain boundaries.