Residual compression mechanical properties after low-speed impact for laminated stitched carbon fiber reinforced aluminum matrix composite

Abstract

Using aluminum alloy ZL301 as matrix and carbon fiber laminated suture fabric as reinforcement, carbon fiber reinforced aluminum matrix (Cf/Al) composites with laminated stitch were prepared by vacuum pressure infiltration process. Through the drop hammer impact test at room temperature, the behavior of impact load and energy change with time was studied. The impact damage morphology was observed by optical microscope and industrial digital X-ray imaging system, and the impact damage mechanism was analyzed. Through the post impact compression (CAI) experiment, the residual strength of the composite along the warp direction under different impact energies was studied, the macro and micro fracture morphologies of the compressed sample were observed, and the compression failure mechanism was analyzed. The results show that the laminated stitched Cf/Al composites have significant local damage under impact load, with obvious pits appeared in the front damage area, and obvious meridional cracks appeared on the back. The crack length increases with the increase of impact energy. The main damage modes are matrix cracking and fiber fracture pulling out. The meridional compressive strength after impact decreases with the increase of impact energy. The compressed composites have transverse cracks extending from the end of the impact crack along the weft direction to the edge of the sample. The severity of yarn structure damage in the macro fracture of compression increases with the increase of impact energy, The micro fractures after compression show uneven morphology after fiber shear fracture.

Keywords

• laminated stitch
• cf/al composite
• low-speed impact
• compressive after impact
• failure mechanism