The Preparation And Compressive Properties Strengthening Of Ordered Porous Aluminum Materials

Porous aluminum is a lightweight material composed of gas phase and pore walls.Traditional disordered porous aluminum has the characteristics of high specific strength and high specific stiffness,but the randomness of its pore structure distribution makes the performance of disordered porous metal unpredictable,which restricts the popularization and application of porous aluminum.Compared with disordered porous aluminum,the structure of ordered porous aluminum has three-dimensional periodicity,which can realize the controllable design of structure and mechanical performance,so that the mechanical properties of the material can be effectively controlled.Therefore,structural design is also a common method to improve mechanical properties.Studies have shown that on the basis of common ordered porous structures,size optimization or topology optimization can change the deformation mode of ordered porous aluminum and improve its mechanical properties.At the same time,as a kind of open-cell aluminum foam,ordered porous aluminum can be filled with other materials to form a continuous interpenetrating composite material.The coupling deformation mechanism between the ordered porous aluminum matrix and the strengthening phase can further improve its mechanical properties and Functional characteristics.This article uses structural strengthening and composite strengthening methods to conduct a preliminary discussion on the strengthening mechanism of ordered porous aluminum: an ordered porous reinforced structure is designed,and corresponding porous aluminum samples are prepared based on the indirect additive manufacturing method;the effect of strengthening structure on the mechanical properties and deformation mechanism of ordered porous aluminum is studied;an in-situ preparation method for preparing continuous interpenetrating ordered/disordered porous composites is proposed,and the effect of disordered porous aluminum on deformation behavior and mechanical properties were studied.The specific content is as follows:(1)Based on the basic cubic ordered porous aluminum,the struts under the load direction(Z-axis)are strengthened and Z-strengthening structure and the gradient/Z-strengthening structure are designed.Based on the indirect additive manufacturing method,the corresponding ordered porous aluminum specimens are prepared.The results of the quasi-static compression experiment show that Z-strengthening enhances the tensile-dominated deformation mechanism of the ordered porous aluminum Z-axis struts during compression deformation,and enhances the elastic modulus and compressive strength of the ordered porous aluminum;gradient/Z-strengthening further increases stiffness and strength of the specimens.The stiffness of the ordered porous aluminum is enhanced,while the toughness of the ordered porous aluminum is reduced,so that the fracture strain is reduced.(2)Study on the preparation method and compressive properties of ordered/disordered porous composite materials.At first,disordered porous aluminum was processed as the framework of infiltration casting,then ZL111 alloy was infiltrated into the preform,and ordered/disordered porous composite samples were successfully prepared.The effects of different pouring temperatures on the interface morphology of ordered porous aluminum and disordered porous aluminum were studied from the macro and micro perspectives,and the best pouring process was obtained.The quasi-static compression results show that the introduction of disordered porous aluminum supports and restrains the ordered porous aluminum matrix,enhances the tensile-dominated deformation mechanism of the ordered porous aluminum Z-axis struts,and improves the compressive performance of the ordered porous aluminum.Ordered/disordered porous materials exhibit a smooth plateau area.The filling of disordered porous aluminum improves the energy absorption capacity of ordered porous aluminum,while keeps the specific energy absorption capacity and energy absorption efficiency basically unchanged.