Enhancement of mechanical properties and microstructure characteristics in laser transmission joining of C1100/glass weld through Taguchi GRA and PCA multi-response optimization

This study thoroughly investigates the enhancement of mechanical properties and microstructural characteristics in C1100/glass welds utilizing an innovative transmission laser joining method. We introduce a sophisticated hybrid polishing technique that seamlessly combines mechanical and electrochemical polishing to achieve a uniform surface. By effectively removing micro-defects and contaminants from the copper plate prior to the glass welding process. Using a strategic combination of the Taguchi method, Grey Relational Analysis, and Principal Component Analysis, we have identified the optimal processing parameters. These expertly determined settings include a laser power of 16 W, a scanning speed of 30 mm/s, a focal plane position of -0.50 µm, and an average surface roughness of only 0.10 µm, demonstrating our dedication to achieving excellence in processing efficiency and quality. The optimized C1100/glass joint demonstrates remarkable characteristics, achieving a welding shear strength of 42.02 MPa that surpasses all previous studies. This significant improvement is particularly noteworthy, even though it reveals some indications of brittle fractures in the separated surface morphologies. The correlation between optimal weld zone, dimension, the expansion of keyhole zone, abundant eutectic Cu-O-SiO ₂ compounds, and Cu ⁺⁽²⁺⁾ -O formation is linked to the resulting highest joining shear strength. This study convincingly demonstrates the capability of generating high-quality copper/glass welds with an affordable laser source, highlighting its significant potential for the production of effective heat dissipation substrates for semiconductors.