Influence of Gas Pressure and Blowing Agent Content on the Formation of Aluminum Alloy Foam

Apart from density and alloy composition, the structure of solid metallic foams determines their mechanical performance. Herein, the effect of ambient pressure on the foaming behavior of AlSi6Cu4 precursors is studied. In situ X‐ray radioscopy is applied while foaming in a furnace chamber pressurized up to 40 bar. The content of the blowing agent (TiH2) is varied for each of the pressures chosen. The foam density and morphology are analyzed quantitatively using time‐resolved X‐ray radioscopy sequences and postsolidification X‐ray tomography data. The optimal content of blowing agent as well as the pore sizes and distributions is found to depend strongly on the ambient pressure. At high pressures very small, round, and uniformly distributed pores are formed and crack formation is avoided during the gas nucleation stage, which helps to prevent structural defects. Adjusting the ambient pressure allows for better control of the foam structure and density, which is relevant for commercial production and application.

[1]  J. Banhart,et al.  Nucleation and growth of gas bubbles in AlSi8Mg4 foam investigated by X-ray tomoscopy , 2021 .

[2]  J. Banhart,et al.  Temperature dependence of film rupture and internal structural stability in liquid aluminium alloy foams , 2020 .

[3]  Z. Cao,et al.  Influence of Ambient Pressure on Cell Structure Evolution in Liquid Aluminum Foam , 2018, Materials Science Forum.

[4]  John Banhart,et al.  Fast Synchrotron X‐Ray Tomography of Dynamic Processes in Liquid Aluminium Alloy Foam   , 2017 .

[5]  J. Banhart,et al.  Influence of the Heating Rate on the Foaming Behavior of Various Aluminium Alloys , 2017 .

[6]  F. García‐Moreno.  Commercial Applications of Metal Foams: Their Properties and Production , 2016, Materials.

[7]  V. Altstädt,et al.  Microcellular to nanocellular polymer foams : Progress(2004–2015) and future directions ; A review , 2015 .

[8]  J. Banhart,et al.  Pressure-Induced Foaming of Metals , 2015 .

[9]  J. Banhart,et al.  Foaming of AA 6061 using multiple pieces of foamable precursor , 2013 .

[10]  J. Banhart,et al.  Suitability of various complex hydrides for foaming aluminum alloys , 2013 .

[11]  J. Banhart,et al.  Recent Trends in Aluminum Foam Sandwich Technology , 2012 .

[12]  John Banhart,et al.  Metal Foaming Investigated by X-ray Radioscopy , 2011 .

[13]  J. Banhart,et al.  Kinetics of coalescence in liquid aluminium foams , 2011 .

[14]  J. Banhart,et al.  Decomposition of TiH2 studied in situ by synchrotron X-ray and neutron diffraction , 2011 .

[15]  J. Banhart,et al.  A study of Mg and Cu additions on the foaming behaviour of Al–Si alloys , 2011, Journal of Materials Science.

[16]  J. Banhart,et al.  Solidification of metal foams , 2010 .

[17]  J. Banhart,et al.  Collapse of Aluminum Foam in Two Different Atmospheres , 2010 .

[18]  John Banhart,et al.  Early pore formation in aluminium foams studied by synchrotron-based microtomography and 3-D image analysis , 2009 .

[19]  J. Banhart,et al.  Influence of Compaction Conditions on the Foamability of AlSi8Mg4 Alloy , 2009 .

[20]  Mark A. Knackstedt,et al.  Imaging of metallic foams using X-ray micro-CT , 2009 .

[21]  J. Banhart.  Advanced tomographic methods in materials research and engineering , 2008 .

[22]  A. Kennedy,et al.  The Effect of Compaction Method on the Expansion and Stability of Aluminium Foams , 2006 .

[23]  Reimund Neugebauer,et al.  Machine Tools With Metal Foams , 2006 .

[24]  J. Banhart,et al.  Modification of titanium hydride for improved aluminium foam manufacture , 2006 .

[25]  John Banhart,et al.  Improvement of aluminium foam technology by tailoring of blowing agent , 2006 .

[26]  J. Grenestedt.  On interactions between imperfections in cellular solids , 2005 .

[27]  J. Banhart,et al.  X-ray radioscopy of liquid metalfoams: influence of heating profile, atmosphere and pressure , 2005 .

[28]  J. Banhart,et al.  Real‐time X‐ray Radioscopy on Metallic Foams Using a Compact Micro‐Focus Source , 2004 .

[29]  U. Ramamurty,et al.  Variability in mechanical properties of a metal foam , 2004 .

[30]  A. Kennedy.  The effect of TiH2 heat treatment on gas release and foaming in Al–TiH2 preforms , 2002 .

[31]  Robert F. Singer,et al.  Modeling of Metal Foaming with Lattice Boltzmann Automata , 2002 .

[32]  A. Kennedy.  Effect of compaction density on foamability of Al–TiH2 powder compacts , 2002 .

[33]  J. Banhart.  Manufacturing routes for metallic foams , 2000 .

[34]  Robert F. Singer,et al.  Influence of processing conditions on morphology of metal foams produced from metal powder , 2000 .

[35]  J. Banhart,et al.  Der Schäumprozeß von Aluminium , 2000 .

[36]  John Banhart,et al.  A study of aluminium foam formation—kinetics and microstructure , 2000 .

[37]  Lorna J. Gibson,et al.  Compressive and tensile behaviour of aluminum foams , 1999 .

[38]  Y. Liu,et al.  Innovative surface modification of TiH2 to fabricate aluminum foam with enhanced mechanical properties , 2018 .

[39]  T. Ginta,et al.  The Influence of Temperature on Stability of Aluminum Foam Cell Wall during Foaming Process , 2018 .

[40]  J. Kováčik,et al.  Effect of foaming parameters on the pore size , 2017 .

[41]  J. Banhart,et al.  Reduced-Pressure Foaming of Aluminum Alloys , 2012, Metallurgical and Materials Transactions A.

[42]  Michael F. Ashby,et al.  Cellular metals and metal foaming technology , 2001 .