Mechanical characterization of the role of defects in sintered FeCrAIY foams

• 来源期刊: 力学学报（英文版）
• 年，卷（期）: 2007,（4）
• 页码范围: 383-398
• 页数: 16页
• 语种: 英文

摘要

Open celled metal foams fabricated through metal sintering are a new class of material that offers novel mechanical and acoustic properties. Previously, polymer foams have been widely used as a means of absorbing acous-tic energy. However, the structural applications of these foams are limited. The metal sintering approach offers a cost-effective means for the mass-production of open-cell foams from a range of materials, including high-temperature steel alloys. In this first part of two-paper series, the mechanical properties of open-celled steel alloy (FeCrAlY) foams were characterized under uniaxial compression and shear loading.Compared to predictions from established models, a signi-ficant knockdown in material properties was observed. This knockdown was attributed to the presence of defects throu-ghout the microstructure that result from the unique fabri-cation process. Further in situ tests were carded out in a SEM (scanning electronic microscope) in order to investigate the effects of defects on the properties of the foams. Typi-cally, the onset of plastic yielding was observed to occur at defect locations within the microstructure. At lower relative densities, ligament bending dominates, with the deformation initializing at defects. At higher relative densities, an additional deformation mechanism associated with mem-brane elements was observed. In the follow-up of this paper,a finite element model will be constructed to quantify the effects of defects on the mechanical performance of the open-cell foam.