**3. Results and Discussion**

### *3.1. Cross-Section Morphology and Size of the Biomimetic Units with Di*ff*erent Carbon Content*

Figure 5 shows the cross-sectional morphology of biomimetic unit with di fferent carbon content. It can be seen that the cross-sectional morphology is parabolic, and the unit is composed of two parts: One part is a fusion zone with a bright white color, and the other part is a heat-a ffected zone (HAZ) in contact with the matrix. Table 3 lists the cross-sectional dimensions of the bionic unit with di fferent carbon contents. It can be concluded from Figure 5 and Table 3 that when the laser processing parameters are the same, as the carbon content increases, the unit characteristics are also increased. The unit characteristics are mainly related to the laser processing parameters and the thermophysical properties of the material [26]. When the laser processing parameters are the same, the thermal conductivity is the determining factor of the unit's characteristics. For carbon steel materials, thermal conductivity increases as the carbon content increases. A material with high thermal conductivity propagates heat at a faster rate, and its fusion zone is wider and deeper. The unit characteristics with di fferent carbon content show this rule.

**Figure 5.** The cross-section of the biomimetic units: (**a**) LR-A1, (**b**) LR-A2, (**c**) LR-A3, (**d**) LR-A4, and (**e**) LR-A5.

**Table 3.** Unit characteristics of di fferent materials.


### *3.2. Microstructure and Phase Composition of Di*ff*erent Carbon Content Matrixes and Bionic Samples*
