Fabrication Of CNT/Al Composite Foamfilled Tubes And Their Crushing Behavior And Energy Absorption Property

With the rapid development of aerospace and transportation,there is an increasing demand for high-performance energy-absorbing components with characteristics of light weight,high strength,and high energy absorption efficiency.Aluminum(Al)foam-filled metallic thin-walled tubes(FFTs)possess high energy absorption property and independent load bearing capacity,which can be used as energy-absorbing structures in the field of transportation and manufacture.However,the methods of improving the strength of FFTs always result in an extra increase in the structure weight.Due to the low density and high strength of carbon nanotube reinforced Al(CNT/Al)composite foams,filling the composite foams can improve the comprehensive performance of FFTs and is one of the effective ways to solve the above problem.But it is difficult to achieve uniform dispersion of CNTs in the metal matrix,which affects the mechanical properties of CNT/Al composite foams.Meanwhile,the research about mechanical performance of CNT/Al composite FFTs has not been reported.This work firstly fabricated CNT/Al composite FFTs by filling CNT/Al composite foams into 6061 Al alloy thin-walled tubes.The composite foams were prepared through the combination of chemical vapor deposition,ball-milling and space-holder method.The crushing behavior,compressive strength and energy absorption capacity of CNT/Al composite FFTs under compressive tests were studied.The interaction between CNT/Al composite foams and alloy tubes was investigated through macroscopic observation and microscopic characterization.Results show that uniformly dispersed CNTs significantly improve the strength of CNT/Al composite foams.The interaction between composite foams and thin-walled alloy tubes endows the CNT/Al composite FFTs with high compressive strength and energy absorption property.The deformation of CNT/Al composite foams is restricted by alloy tubes,when the CNT/Al composite foams support the alloy tubes.The deformation resistance of CNT/Al composite foams and the supporting effect of the composite foams on alloy tubes increase gradually with the deformation process,which greatly improve the enhancement effect on CNT/Al composite FFTs.The support of the composite foams on the alloy tubes and the filling of the folds greatly stabilize the deformation process.The plateau stress and energy absorption capacity of CNT/Al composite FFTs are nearly 3.5 and 3.7 times higher than those of thin-walled alloy tubes,respectively.Meanwhile,the CNT/Al composite FFTs have higher specific energy absorption than that of thin-walled alloy tubes.The CNT/Al composite FFTs significantly improve the energy absorption performance with slightly increasing the weight,which shows a good compromise between structure weight and energy absorption capacity.This work provides certain guiding significance for the design and fabrication of light-weight and high-strength energy-absorbing structures.