The feasibility research on shot-peen forming of the novel fiber metal laminates based on aluminum-lithium alloy

The feasibility on shot-peen forming of the novel fiber metal laminates based on aluminum-lithium alloys (NFMLs) was investigated to seek a desired forming method. The failure behavior of shot-peened NFMLs was then examined using C-scan ultrasonic testing and scanning electron microscopy (SEM). The changes in surface roughness and formed curvature were also analyzed. The unique deformation behavior of the laminates comparing with monolithic materials was revealed. The results indicated that NFMLs were feasible to manufacture by shot-peen forming. High shot-peening intensity and large ball sizes caused serious plastic deformation in shot-peened surface with evident stress variation at the metal/fiber interface. This led to interface delamination and fiber breakage. Moreover, increased but quite uniform surface roughness was obtained for the shot-peened laminates. Large-size ball was found beneficial for improving the surface quality when achieving the same shot-peening intensity. Also, the ball type and size significantly affected the formed curvature of NFMLs due to the complex effects of fiber layers on the formation behavior. Overall, the AZB425 ball was found more beneficial in improving the surface quality and formed curvatures. The minimal curvature radius reached approximately 200 mm within the investigated processes.