## 3 Results and Discussion
### Tribological Behavior  
Figure 7 shows the friction coefficient curves of CS_QAT and CS_IQAT at different frequencies. It is observed that the friction coefficient curves of CS_IQAT specimens are lower than those of CS_QAT specimens at the same frequency and are relatively smooth. This difference is closely related to the finer and more uniform microstructure  
Figure 5: Hardness and impact toughness of CS_QAT and CS_IQAT. Figure 6: Stress–strain curves of CS_QAT and CS_IQAT. and higher hardness and yield strength of CS_IQAT specimens. The fine and uniform microstructure can better distribute and withstand external stresses, preventing localized stress concentration and helping to reduce micro-unevenness and micro-crack formation on the material surface. Higher hardness reduces the degree of plastic deformation and wear of the material surface during friction, thus reducing friction. Materials with high yield strengths are less prone to deformation, helping to maintain surface integrity and contact area stability. The surface of CS_IQAT specimens is smoother, more wear-resistant, and has a more stable contact area during friction. The combination of these factors results in a lower and smoother coefficient of friction for CS_IQAT than for CS_QAT. In addition, the friction coefficient curves of the two gradually increase as the frequency increases. This is because the increase in frequency leads to more frequent relative motion between the friction surfaces, the heat generated by friction cannot be emitted in time, and the heat accumulates in the friction contact area. The increase in temperature intensifies the softening of the friction surface material and increases the plastic deformation of the surface, which leads to an increase in the coefficient of friction. The average friction coefficient is shown in Figure 8, and the results are consistent with the above. Figure 9 shows the relative wear rate of CS_QAT and CS_IQAT at different frequencies. It is observed that the relative wear rate of CS_QAT and CS_IQAT tends to increase as the  
Figure 8: Average friction coefficient at different frequencies. Figure 7: Friction coefficient curves of CS_QAT and CS_IQAT at different frequencies: (**a**) CS_QAT; (**b**) CS_IQAT. load increases. The relative wear of CS_IQAT is significantly lower than that of CS_QAT at the same frequency. This is related to the fact that CS_IQAT has a fine and uniform microstructure and higher hardness and yield strength, and its surfaces are smoother, more wear-resistant, and have a more stable contact area during the friction process. At frequencies of 2 Hz, 3 Hz, 4 Hz, and 5 Hz, the relative wear rates of CS_QAT specimens were 5.2 mm\({}^{3}\)/N-m, 8.5 mm\({}^{3}\)/N-m, 9.8 mm\({}^{3}\)/N-m, and 13.3 mm\({}^{3}\)/N-m, whereas those of CS_IQAT specimens were 3.0 mm\({}^{3}\)/N -m, 5.0 mm\({}^{3}\)/N-m, 6.5 mm\({}^{3}\)/N-m, and 9.6 mm\({}^{3}\)/N-m, respectively. The relative wear rates of the CS_IQAT specimens constitute 58% at 2 Hz, 59% at 3 Hz, 66% at 4 Hz, and 72% at 5 Hz relative to the CS_QAT specimen. Figure 10 shows the width and depth of wear of CS_QAT and CS_IQAT at different frequencies. It can be observed that the depth of wear marks of CS_QAT and CS_IQAT increases gradually with the increase in frequency, which is mainly due to the increase in frequency that leads to an increase in the temperature of the friction surface, which makes the material more prone to plastic deformation and wear. It is also observed that the depth of wear marks of CS_IQAT is much smaller than that of CS_QAT at the same frequency. The three-dimensional morphology is detailed in Figure 11. The friction and wear performance of CS_IQAT is better than that of CS_QAT, and it is possible to replace CS_IQAT with CS_QAT, which can be used in harsher environments. Figure 10: Wear width and depth plots of CS_QAT and CS_IQAT at different frequencies: (**a**) CS_QAT; (**b**) CS_IQAT. Figure 9: Relative wear rates of CS_QAT and CS_IQAT at different frequencies.