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Carbon fiber reinforced plastic (CFRP) has been widely used in aerospace, shipping and automobile, et al. However, realizing a high strength joint between the CFRP and metals is still an unsolved industrial problem. In this study, an experimental investigation on the mechanism of laser direct joining between 304 stainless steel and CFRP was carried out, and a method to strengthen the joint by filling PPS laminae between metal and CFRP was present. The effect of the laser power and the traveling speed on the joint strength were studied. The strength of joint was also tested by using electro-mechanical universal testing. Experimental results showed that: (1) Cross-sectional photos revealed that the melted PPS flowed into micro-cavity of metal surface and a mechanical bonding was formed. (2) The shear strength reached 15.7MPa when the energy density was 45.71J/mm2, which was determined by the power of 320W, the traveling speed of 5 mm/s, and the defocusing distance of 20 mm. The simulation of temperature field was conducted to provide theoretical support for the experimental results. These results showed that the bonding strength of the metal-CFRP could be improved by filling PPS laminae between the CFRP and the 304 stainless steel in the welding process.Carbon fiber reinforced plastic (CFRP) has been widely used in aerospace, shipping and automobile, et al. However, realizing a high strength joint between the CFRP and metals is still an unsolved industrial problem. In this study, an experimental investigation on the mechanism of laser direct joining between 304 stainless steel and CFRP was carried out, and a method to strengthen the joint by filling PPS laminae between metal and CFRP was present. The effect of the laser power and the traveling speed on the joint strength were studied. The strength of joint was also tested by using electro-mechanical universal testing. Experimental results showed that: (1) Cross-sectional photos revealed that the melted PPS flowed into micro-cavity of metal surface and a mechanical bonding was formed. (2) The shear strength reached 15.7MPa when the energy density was 45.71J/mm2, which was determined by the power of 320W, the traveling speed of 5 mm/s, and the defocusing distance of 20 mm. The simulation of temperature fie...

To improve the copper absorption coefficient to lasers, a black-treating method is proposed. With this method, the reflection coefficient of the copper to lasers with wavelength of 1064 nm can be reduced from 95% to 15.5%. The process of copper laser welding with the thickness of 0.3 mm is studied by a 500 W fiber laser machine. The shape, strength and micro-hardness of the welding seam under different welding velocity and defocus amount are analyzed and the optimum parameters are found. Moreover, the laser welding quality of copper with black-treating is compared with that with graphite coating. The results show that the micro-hardness and strength of the welding seam of copper with black-treating are better than that with graphite coating.