Fabrication And Mechanical Study Of Carbon Nanotube Reinforced Hollow Microlattice Materials

Creating lightweight but strong materials are eternal pursuit of aerospace industry.Hollow microlattice material,composed of orderly configured and connected hollow tubes whose wall thickness is in nano/microscale,is a category of novel metamaterials with ultralight,ultrastiff,ultrastrong mechanical performance and multiple functions such as vibration control,energy absorption,heat insulation and catalysis carrying,leading to a wide variety of promising applications in aerospace industry.However,confining to underdeveloped manufacturing methods in present the mechanical properties of microlattice materials are inferior to that predicted by theories.Researching mechanical properties of microlattice materials and developing methods of improving elastic modulus and strength are of great importance to microlattice materials.This work is dedicated to reviewing mechanical design theories of microlattice materials and developing a renewed manufacturing method combining carbon nanotubes(CNTs)as reinforcement and microlattice materials.The effect of CNTs on mechanical performance of hollow microlattice materials is investigated by in-situ compressive tests.This work at first reviews the micro-structural design of microlattice materials and discusses the rationale behind Gibson & Ashby scaling law for mechanical characterization.Then,as a renewed manufacturing method,following micro-stereolithography-based additive fabrication of a sacrificial microlattice template the Ni-P-CNT composite electroless plate is carried out,after which the template is etched by chemicals.Through in-situ compression tests it is found that,in comparison with Ni-P counterparts,elastic modulus and compressive strength of Ni-P-(3.08 wt.%)CNT hollow microlattice materials are increased by factors of 2.4~2.6 and 2.0~2.9,respectively.By meso mechanical analysis,it is deemed that the enhancement by CNTs is attributed to the shear-lag effect and shear band impediment effect induced by interaction between CNTs and Ni-P amorphous material.