## 3 Results and Discussion
### Creep Assessment
#### 3.3.1. Creep Behaviour Assessment--Metallurgical Approach  
Prior to the application frame, a typical creep depth, as a function of the holding time diagram, can be seen in Figure 10a. After the application of the calculation frame on the curves of the type of Figure 10a, the diagrams \(ln\left(\frac{1}{\hbar}\frac{dh}{dt}\right)\) as a function of \(ln(H)\) can be constructed (Figure 10b), based on which the stress exponent \(\mathbf{n}\) and the stress sensitivity factor \(\mathbf{\mathrm{m}}\) can be calculated. Table 3 summarizes all the crucial parameters that are the outcome of the application of the calculation frame, and which are important for analyzing the creep response of the system at the different testing parameters. Based on the data in Table 3, a series of diagrams can be produced in order to assist both the visualization of the obtained results and the analysis of the creep response. As such, Figure 11 presents the effect of the different testing parameters on the net creep (h\({}_{\mathrm{creep}}\)) depth. Figure 12 shows a similar analysis of the maximum shear stress (\(\tau_{\mathrm{max}}\)). Figure 9. Loading stage curves for preset depth 2000 nm: (**a**,**b**) loading speed 13.4 mN/s, (**c**,**d**) loading speed 4.4 mN/s, and (**e**,**f**) loading speed 2.24 mN/s. Figure 10: (**a**) typical diagram of creep depth (hcreep) as a function of the holding time and (**b**) typical curve of \(ln\left(\frac{1}{h}\frac{dh}{dt}\right)\) as a function of \(ln(H)\). Figure 11: The effect of different testing parameters on the net creep depth (h\({}_{\text{crep}}\)). \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multicolumn{2}{c}{**Testing Variables**} & \multicolumn{8}{c}{**Measured Parameters (Outcomes)**} \\ \hline
**Preset** & **Loading** & **Speed** & **Crep** & **Peak** & **Maximum** & **Strain Rate** & **Strain Rate** & **Critical** & **Volume for** & **Net Creep** \\
**Depth** & **Speed** & **Duration (s)** & **Hardness** & **Stress** & **Exponent** & **Sensitivity** & **Pastor** & **Dislocation** & **Depth** (nm) \\ \hline
**Un  
Figure 13 shows the effect of the different testing parameters on the stress exponent \(n\), and Figure 14 shows the effect of the same parameters on the critical volume for dislocation nucleation. Figure 12: The effect of the different testing parameters on the maximum shear stress (\(\tau_{\max}\)). Figure 13: The effect of the different testing parameters on the stress exponent \(n\). Based on the information provided by Table 3 and Figures 11-14, the following points can be addressed:  
1. Figure 10a presents a typical indentation displacement (\(\Delta\)h) vs. time (t) curve for the holding stage (creep stage) along with the typical correlation parameters. These correlation parameters were obtained by applying a power law fitting. This observation is very important. It has been proposed by many researchers that a power law fitting of the creep displacement as a function of the holding time suggests a dislocation-driven creep deformation and, more specifically, a dislocation glide mode [2; 5; 9; 11; 12; 34]. Despite the fact that [PERSON] et al. [4], in their early work, pointed out that a power law creep behavior is mainly associated with dislocation climb and/or dislocation climb-glide mixed mode at intermediate to high temperatures, in their concluding remarks, they admit that at low temperatures, dislocation glide-induced plasticity must be the predominant mechanism due to the high stresses being developed within the elastic-plastic zone. As such, in the present effort, since a power law of extremely good fitting was observed, dislocation glide is considered the main creep deformation mechanism. 2. **Net Creep deformation (h\({}_{creep}\)):** The first important observation is the fact that, irrespective of the testing conditions, creep deformation increases as the creep period increases. This is expected since the more prolonged the time, the more time for the available dislocations to move and provide plastic flaws, i.e., plastic deformation.