盐球渗透铸造法制备开孔泡沫铝的孔结构及压缩性能

使用圆盘造粒机制备近球形的NaCl颗粒，并将其用于渗透铸造制备开孔泡沫铝。盐球的平均抗压缩强度为3.9 MPa，在超声波清洗机中可在5 min内完全塌陷。通过控制热压烧结时间为0.5～2 h，热压温度700℃，可制备堆积密度在0.66～0.83 g/cm³的预制体。延长热压烧结时间会使开孔泡沫铝的孔径从0.48 mm增加到1.16 mm，孔隙率从64%增加到82%。压缩实验结果表明，不同孔隙结构下泡沫体的宏观变形特征基本相同，均表现出逐层塌陷的变形特征。此外，泡沫铝的致密化应变值、弹性模量、平台屈服应力和能量吸收能力均随着孔隙率的增加而降低。当孔隙率为64%时，能量吸收能力最大(15.0 MJ·m^-3)。

Pore Structure and Compressive Properties of Open-Cell Aluminum Foams Prepared by Infiltration Casting Based on NaCl Space-Holder

Nearly spherical NaCl particles prepared by a disc granulator were used to produce open-cell aluminum foams via infiltration casting. The average compressive strength of the salt balls is 3.9 MPa, and they can be completely collapsed within 5 min in the ultrasonic cleaner. By controlling the hot-pressure sintering duration as 0.5?2 h and the hot-pressing temperature at 700 °C, the preforms with bulk density of 0.66?0.83 g/cm³ can be prepared. Prolonging the duration of hot-pressure sintering can increase the pore size of the open-cell aluminum foams from 0.48 mm to 1.16 mm, and also increase the porosity from 64% to 82%. Compression test results show that the macroscopic deformation characteristics of the foams with different pore structures are basically the same, and they all exhibit the deformation characteristic of layer-by-layer collapse. In addition, the densification strain value, elastic modulus, plateau yield stress, and energy absorption capacity of open-cell aluminum foams are al decreased with increasing the porosity. The energy absorption capacity is the largest (15.0 MJ·m^-3) when the porosity is 64%.