1：Experimental Design and Method Selection:

Pulsed laser welding was used with a Zn interlayer of varying thicknesses (

2：05 mm, 1 mm, 2 mm, 5 mm) between AZ31B Mg alloy and T2 pure Cu plates. The effects of the Zn interlayer thickness on the microstructure and properties of the joint were studied. Sample Selection and Data Sources:

AZ31B Mg alloy (1 mm thick) and T2 pure Cu (

3：5 mm thick) plates were used. Zn foils of different thicknesses were inserted between them. List of Experimental Equipment and Materials:

Pulsed Nd: YAG laser (WF-300), optical microscopy (OM, OLYMPUS GX51), scanning electron microscopy (SEM, ZEISS SIGMA500), transmission electron microscopy (TEM, JEM-2100), energy-dispersive X-ray spectrometry (EDX), Vickers hardness measurement (HV-10MP), universal testing machine for materials (SUNS UTM 5305).

4：5). Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: The plates were ground, scrubbed with alcohol, and dried before welding. The welding parameters included an instantaneous laser power of

5：5 kW, a welding rate of 4 mm/s, single-point energy of 31 J, and an Ar gas flow rate of 10 L/min. Data Analysis Methods:

The microstructure was observed by OM, SEM, and TEM. EDX was used for elemental distribution analysis. Vickers hardness and shear strength were measured. First-principles calculation based on density-functional theory was conducted to analyze the electronic structure and properties of the joint.