Achieving an improved formability and microstructure in infrared-blue laser hybrid cladding of pure Cu on AlSi7Mg substrate via infrared laser beam circular oscillating scanning

Infrared-blue laser hybrid (I-BLH) has been proven to have high power conversion efficiency and stability in the cladding process of some high-reflectivity alloys for the infrared laser, e.g., Cu-alloys and Al-alloys. The highly concentrated energy input in the overlap zone between the infrared laser and blue laser beam may lead to the formation of severe micro-pores and coarser columnar grains. To solve this difficulty, a new way, infrared laser beam circular oscillation, was successfully used in the cladding process of pure Cu on the rolled AlSi7Mg substrate. The circular oscillation of the infrared laser beam reduces the defects in the hybrid cladded samples and increases the relative density to - 100 %. Besides, the circular oscillating scanning decreases the surface roughness of the cladded samples to - 40 mu m. Finally, the circular oscillating scanning is conducive to forming equiaxed grains in the cladded samples, with a minor coarsening of the Al-dendrite and Al2Cu phases. The main influencing factors for eliminating defects and improving microstructures of the I-BLH cladded samples are the cooling rate, temperature gradient, and oscillating effect. Thus, infrared laser circular oscillation scanning shows a great potential to improve the quality of the I-BLH cladding technology and contribute to applications in the further industry.