3.2.1. The Microstructure of the Matrix

Figure 6a–e shows the microstructure of the matrix materials. It can be seen that the matrix structure of the five materials is the same, consisting of pearlite and ferrite; with an increase of carbon content, the ferrite content decreases, and the pearlite content increases.

**Figure 6.** The microstructure of base material samples: (**a**) A1, (**b**) A2, (**c**) A3, (**d**) A4, and (**e**) A5.

3.2.2. The microstructure of the unit

Figure 7a–e shows the microstructure of the unit remelting zone of the laser biomimetic sample. Although the carbon content of the base material is different, the microstructure of the laser fusion zone is the same (which is composed of lath martensite and plate martensite). With an increase of carbon content, the content of the plate martensite gradually increases, and the content of lath martensite decreases. This is due to the different carbon content of the material.

**Figure 7.** The microstructure of remelting zone of biomimetic unit: (**a**) LR-A1, (**b**) LR-A2, (**c**) LR-A3, (**d**) LR-A4, and (**e**) LR-A5.
