Fabrication and High-Temperature Compressive Behavior of Unique Multi-Sheet Stacked Block Ni–Cr–Al Metallic Foam

Abstract

Large unique block Ni–Cr–Al superalloy foam was fabricated using a combination method of powder-alloying, multi-sheet stacking, and hot compression processes. Subsequently, the compressive properties and deformation behaviors of multi-sheet stacked block metallic foam were investigated from room temperature to 1073 K. The analysis of the resulting structural characteristics of the block foam showed that the interfaces between the sheets have complex strut interactions, such as contacted (deformed) and intersected struts. The relative density was measured as 2.93% for sheet foam and 4.90% for block foam. The compressive deformation of sheet and block Ni–Cr–Al foams showed the typical compressive stress–strain curves of plastically deformable metallic foams regardless of foam type. However, different deformation behaviors in the plateau regions were detected based on the type of foam. It is noteworthy that the yield strength of block foam showed a relatively lower value than that of sheet foam, even though the block foam had higher relative density. The existence of unique interfaces in the multi-sheet stacked block foam may have affected strength and plastic deformation. Finally, distinct compressive behaviors related to the structural and microstructural characteristics of block Ni–Cr–Al foam are discussed.