Material removal mechanism of cryogenic-laser assisted cutting for SiCp/Al composites

Aluminium-based silicon carbide (SiCp/Al) is widely used for the fabrication of mechanical structural components of optical systems, due to its excellent mechanical properties. However, owing to the significant differences in material properties between the soft Al matrix and hard SiC-reinforced particles, achieving an ultra-smooth surface of SiCp/Al composites remains challenging. In this study, a novel cutting approach combining cryogenic treatment with laser heating is proposed to improve the machinability of SiCp/Al composites. Nanoindentation tests reveal that low-temperature treatment significantly increased the hardness of SiCp/Al composite materials by approximately 46.4 % (from approximately 6.55 GPa at room temperature to approximately 9.599 GPa at 233 K), and increased the Young’s modulus by approximately 20 %. Then, groove cutting was conducted to investigate the ductile machinability of SiCp/Al. The results showed that Cryogenic-Laser Assisted Cutting (CLAC) achieves high-quality surface with lower cutting force, whereas ordinary cutting, cryogen-assisted cutting, and Laser Assisted Cutting (LAC) resulted in various defects. These results suggest that CLAC enhances the surface quality, offering a potential solution for high-precision manufacturing of SiCp/Al composites. Finally, molecular dynamics simulations were performed to explain the material removal mechanism during CLAC. The simulation results reveal that low-temperature assistance can enhance the interfacial bonding between SiC particles and the Al matrix, thereby suppressing the debonding of SiC particles.