Manufacturing and Investigation of In Situ and Ex Situ Produced Aluminum Matrix Foam‐Filled Tubes

Abstract

Composite metal foams (CMFs) are hybrid structures, which are usually produced from separate parts, and not in one step as functional, structural elements. Functional CMFs are characterized by high strength, high stiffness, and extreme energy absorbing properties compared with conventional metallic foams, which allow them to be used as load‐bearing and energy absorbing elements. Test specimens are made in AlMgSi0.5 tubes with the wall thickness of 5 mm. AlSi12 casting alloy is used as matrix material. To ensure the foam structure porosity, lightweight expanded clay aggregate particles (LECAPs) are used with unimodal and bimodal size distribution. The results show that low‐cost unimodal and bimodal foam‐filled tubes (FFTs) can be produced in situ by inert gas pressure infiltration. Besides their low density, these CMFs achieve high strength, high toughness, and special, functional properties compared with simple metallic foams. After heat treatment, in situ produced bimodal FFTs have the highest energy absorption capacity of an average of 67.2 J cm−3, which is 9% higher than the average value of the ex situ FFTs. Therefore, it is advantageous to produce in situ FFTs, because with proper manufacturing, it requires less machining, making the production easier, while achieving better compressive properties.