A Novel Approach for Fabricating In Situ Aluminum Foam-Filled Carbon Steel Tubes via Hot-Dip Aluminizing

Herein, a new process combining hot-dip aluminizing (HDA) technology with melt foaming method is developed to prepare in situ aluminum foam-filled AISI 1020 tubes with metallurgical bonding which has the advantages of low production cost and wide range of product sizes. Detailed microstructural characterization is performed at the foam/tube interface of in situ foam-filled tubes (FFTs). Quasistatic compressive experiments are carried out to investigate deformation behavior and mechanical properties of ex situ and in situ FFTs with and without HDA pretreatment (in situ-HDA FFTs and in situ-without HDA FFTs). The results indicate that HDA pretreatment effectively improves the wettability between the steel tube and the aluminum melt, enhancing the interfacial bonding quality between the two. Under compressive loading, in situ-HDA FFTs axially deform in an efficient mixed mode, showing superior energy absorption capability as compared to the empty heat treatment (empty-HT) tubes. Specifically, in situ-HDA FFTs have the highest specific energy absorption of an average of 16.6 kJ kg-1 which is 13% higher than the average value of ex situ-HT FFTs.