Preparation And Compression Energy Absorption Performance Of Carbon Nanotube Reinforced Open-cell Foamed Aluminum Alloy

Aluminum Foams,as a representative of structural and functional integration materials,have shown broad application requirements and prospects in many fields.In order to further obtain high-performance aluminum foams,carbon nanotubes(CNTs)reinforced aluminum foam has become a current research hotspot.Studies have shown that by adding an appropriate amount of alloying elements into metal matrix composite materials,the problem of reducing of material plasticity caused by the CNTs can be greatly alleviated,and the comprehensive mechanical properties of the material can be further improved.Therefore,it is of great significance to systematically study the effect of alloying elements on the structure and properties of CNTs-reinforced Al matrix composite foams(CNTs/Al composite foams).The main research contents and results of the present work are as follows:The CNTs/Al composite powders were prepared by CNTs adding method,and its process parameters were optimized.The results show that the CNTs/Al composite powder with uniformly adsorbed CNTs can be obtained by magnetically stirring and drying the flake-shaped Al powder and CNTs;When the content of CNTs was 2.5 % and the milling time was 8 h,the yield strength of the composite foams was the highest,reaching about 19.2 MPa,and the energy absorption performance was also significantly improved.The CNTs/Al-Si composite foams were prepared by ball milling combined with space holder method.The effects of sintering temperature and Si content on the microstructure,compression properties and energy absorption characteristics of CNTs/Al-Si composite foams were studied.The results show that when the sintering temperature is 600 °C,the compression and energy absorption performance of CNTs/Al-7Si composite foams is the best.Compared with CNTs/Al foams,the plasticity and strength of the CNTs/Al-7Si composite foams were significantly improved,and the yield strength,platform stress and energy absorption performance were increased by 58.5 %,117.8 % and 77.3 %,respectively.CNTs/Al-Mg composite foams were prepared by ball milling combined with space holder method.The effects of Mg addition and sintering temperature on the microstructure,compression and energy absorption properties,and failure mechanisms of CNTs/Al-Mg composite foams were studied.The results show that increasing the temperature within the allowable range improves the strength and plasticity of the material.The yield strength of the CNTs/Al-3Mg composite foams stabilizes in a higher range during compression,and the densification strain of the curve increases,and the compressive stress remains stable for a long time.The deformation of the pore wall during the entire compression process has both brittle and ductile fracture characteristics,which is a good energy absorption material.