We developed a novel process for foaming aluminum and its alloys without using a blowing agent. The process involves a designated apparatus in which molten aluminum and its alloys are first foamed under reduced pressure and then solidified quickly. Foaming was done for pure aluminum (99.99 pct) and AlMg5 alloy not containing stabilizing particles and AlMg5 and AlSi9Mg5 alloys containing 5 vol pct SiO2 particles. We discuss the foaming mechanism and develop a model for estimating the porosity that can be achieved in this process. The nucleation of pores in foams is also discussed. © 2012 The Minerals, Metals &amp; Materials Society and ASM International.

Manas Mukherjee

Department of Metallurgical and Materials Engineering

G. S. Vinod Kumar

F. Garcia-Moreno

J. Banhart

ALUMINUM AND ITS ALLOYS

FOAMING MECHANISM

MOLTEN ALUMINUM

PURE ALUMINUM

REDUCED PRESSURE

Aluminum

Blowing agents

Aluminum alloys

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

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IIT Madras

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science

Abstract: Aluminium and Al-TiB2 closed-cell foams were produced by a recently developed foaming method called melt injection technique where bubbles are created by air entrainment. The macro- and microstructures of the foams were characterised by X-ray tomography and scanning electron microscopy, respectively. Mechanical properties were evaluated by quasi-static compression tests. Al-TiB2 foam exhibited finer cells and better mechanical properties compared to Al foam. Also, the structural and mechanical properties of these foams were compared with closed-cell foams produced by other existing methods. Graphic abstract: [Figure not available: see fulltext.]. © 2019, The Indian Institute of Metals - IIM.

Transactions of the Indian Institute of Metals

Al and Al-TiB2 Foams Produced by Melt Injection Technique

Pressure-induced foaming (PIF) of metals is a foaming technique in which blowing agent free compacted metal powders are foamed. The method consists of heating hot-compacted metallic precursors to above their melting temperature under gas overpressure and foaming them by pressure release. This study focuses on PIF of Al99.7 and AlSi7 alloys under both air or Ar and overpressures up to 9&nbsp;bar. In situ x-ray radioscopy allows us to follow the foaming process and to perform quantitative analyses of expansion, foam morphology, and coalescence rate. Mass spectrometry helps to identify hydrogen as the foaming gas. Adsorbates on the former powder particles are found to be the primary gas source. Various advantages of this new method are identified and discussed. © 2015 The Minerals, Metals &amp; Materials Society.

Pressure-induced foaming of metals

ASM Failure Analysis Case Histories: Air and Spacecraft

Uncommon Failures in Aluminum Alloys

Metallurgical and Materials Transactions A

Foamability of MgAl2O4 (Spinel)-Reinforced Aluminum Alloy Composites

Acta Materialia

Solidification of metal foams

Metallurgical and Materials Transactions B

A Novel Characterization Technique to Determine Pore Susceptibility of Alloying Elements in Aluminum Alloys

Advanced Tomographic Methods in Materials Research and Engineering

INTRODUCTION

Reduced-pressure foaming of aluminum alloys

Journal	Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Open Access	No