Large-scale CFRTP-Al alloy stacks laser assisted joining with a reciprocating feed method

No-bolt joining Aluminum alloys and carbon fiber reinforced thermoplastic (CFRTP) are popular topic in aerospace and automation field, in which laser fusion joining is characterized by high-quality and high-efficiency. However, high-energy laser input and material property differences often cause interface temperature difficult to control, leading to thermal defects, which become more challenging as stacks size increases. This study investigates the temperature distribution and thermal defect formation at the Al/CFRTP lap interface under laser heating, based on one-dimensional heat transfer in dissimilar materials. A laser reciprocating feed method for regulating lap interface temperature is proposed. A quantitative evaluation standard for fusion joining quality was established based on lap interface temperature characteristics. Using this standard, an empirical model was developed to optimize process parameters, providing an optimized parameter set and a fusion joining strength prediction model. Experimental results show that the optimized process parameters improve lap interface temperature uniformity by an average of 47 %, while the joint strength in high-strength zones exceeds 20 MPa, offering effective guidance for laser fusion joining of similar Al/CFRTP stack structures.