Study on Deformation of Closed-Cell Aluminum Foam in Different Solid–Liquid–Gas Coexisting State

Abstract

The deformation of closed-cell aluminum foam (CAF) in different solid–liquid–gas coexisting state was studied in this paper. The results showed that the most suitable temperature of the CAF deformation was about 635 °C, which made the CAF have maximum deformation, but its characteristic parameters changed slightly. Moreover, the multi-grain cell wall and small size cell were helpful to the CAF deformation in the solid–liquid–gas coexisting state. When the CAF deformed at 635 °C, the inter-granular solidification microstructure and part of the primary α-Al grain were melted into liquid. The fixed or inter-locked primary α-Al grain was released and changed into the distributed discretely near-spherical grain, making the cell wall have good thixotropy. At the same time, the gas pressure in the cell was recovered to the foaming stage, so the gas pressure could be close to the flow stress of cell wall. During the CAF deformation in the solid–liquid–gas coexisting state, the cell wall deformed in thixotropic under the supporting and coordinating of the gas pressure in the cell, meanwhile, the cell was moved following the cell wall deformation. Therefore, the CAF deformation was affected by the types of the cell walls and the cell size. In this paper, the mold forming process was used to study the influence of temperature on deformation of the closed-cell aluminum foam (CAF) that in solid–liquid–gas coexisting state. When the CAF was deformed in solid–liquid–gas coexisting state who has strong deformation capacity, moreover, whose characteristic parameters are largely unchanged. However, shape forming of the closed cell aluminum foam only could be realized in specific solid–liquid–gas coexisting state, which was mainly related to the deformation temperature.