基于原位观测的泡沫金属细观与宏观压缩实验研究

采用原位观测的方法研究了脆性泡沫铝材料在压缩载荷下细观与宏观断裂破坏规律和吸能机理。针对多孔泡沫金属材料提出一种细观原位加载实验方法,采用特别设计与制备的试件,在S570扫描电镜下研究了特定胞孔在压缩过程中孔壁的失效顺序和破坏规律,并揭示了能量吸收的细观机理。对块体材料的宏观压缩实验表明,脆性泡沫铝是以多个断裂带的形式破坏。研究发现,孔壁缺陷和胞孔形态缺陷是诱发断裂带形成与发展的重要因素。依据尺寸效应对细观与宏观实验下泡沫铝的性能进行了比较。

On the Mesoscopic and Macroscopic Compression Tests of Metallic Foams Based on In Situ Observation

The failure regularity and energy absorption mechanism of brittle Al alloy foam materials under compression loading were tested in both mesoscopic and macroscopic scale.An in situ observation method in the mesoscopic scale was proposed for porous metallic foams.With the specially designed and machined samples,the failure sequence and fracture behaviour of the specific cell were studied with the aid of S570 scanning electron microscope,and the energy absorption mechanism was revealed.Macroscopic compression tests for bulk Al foams show that cells fractured into multiple bands.It was found that defects in cell wall and cell morphology are important factors for fracture bands initiation and developing.Considering the size effects,the mechanical properties obtained from respective mesoscopic and macroscopic tests were compared.