Achieving crack-free CuCrZr/AlSi7Mg interface by infrared-blue hybrid laser cladding with low power infrared laser

A coaxial infrared-blue hybrid laser with low power infrared laser was used to clad high-reflectivity CuCrZr alloy on the AlSi7Mg substrate, and the formability and solidification behaviour in cladding with the high crack sensitivity materials under the infrared, blue and hybrid laser were compared. We demonstrated that the combination of a small power (100–200 W) infrared laser with 960 W blue laser can effectively eliminate the cracking and balling phenomenon existed in the cladded samples under the action of both infrared and blue laser. Compared with the coarser Al-dendrite (1.37–2.50 µm) and Al2Cu phase in the cladded tracks formed under the infrared laser (2600 W) and the hybrid laser with high infrared power (1000–2600 W), finer Cu-dendrite (0.45–0.89 µm) is the main precipitation phase in the cladded tracks under the combination of 960 W blue laser and low power infrared laser (100–200 W). The improvement of the formability and solidification behaviour should be related to the stable and high absorption rate (∼65%) of blue laser, as well as the concentrated power density of low power infrared laser. This work validated the potential of the infrared-blue hybrid laser with low power infrared laser in cladding with high-reflectivity and high crack-sensitivity alloys.