https://mech.pg.edu.pl/documents/14057592/14057638/1611.pdf

Fabrication methods of porous metals for use in orthopaedic applications

Porous metals and metallic foams are presently the focus of very active research and development activities. There are currently around 150 institutions working on metallic foams worldwide, most of them focussing on their manufacture and characterisation. Various companies are developing and producing these materials which are now being used in numerous industrial applications such as lightweight structures, biomedical implants, filters, electrodes, catalysts, and heat exchangers. This review summarizes recent developments on these materials, with particular emphasis on research presented at the latest International Conference on Porous Metals and Metallic Foams (MetFoam 2007).

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Porous Metals and Metallic Foams: Current Status and Recent Developments†

In this paper, we examine prospects for the manufacture of patient-specific biomedical implants replacing hard tissues (bone), particularly knee and hip stems and large bone (femoral) intramedullary rods, using additive manufacturing (AM) by electron beam melting (EBM). Of particular interest is the fabrication of complex functional (biocompatible) mesh arrays. Mesh elements or unit cells can be divided into different regions in order to use different cell designs in different areas of the component to produce various or continually varying (functionally graded) mesh densities. Numerous design elements have been used to fabricate prototypes by AM using EBM of Ti-6Al-4V powders, where the densities have been compared with the elastic (Young) moduli determined by resonant frequency and damping analysis. Density optimization at the bone-implant interface can allow for bone ingrowth and cementless implant components. Computerized tomography (CT) scans of metal (aluminium alloy) foam have also allowed for the building of Ti-6Al-4V foams by embedding the digital-layered scans in computer-aided design or software models for EBM. Variations in mesh complexity and especially strut (or truss) dimensions alter the cooling and solidification rate, which alters the alpha-phase (hexagonal close-packed) microstructure by creating mixtures of alpha/alpha' (martensite) observed by optical and electron metallography. Microindentation hardness measurements are characteristic of these microstructures and microstructure mixtures (alpha/alpha') and sizes.

Next-generation biomedical implants using additive manufacturing of complex, cellular and functional mesh arrays

A ceramic-reinforced aluminum matrix composite is formed by contacting a molten aluminum-magnesium alloy with a permeable mass of ceramic material in the presence of a gas comprising from about 10 to 100% nitrogen, by volume, balance non-oxidizing gas, e.g., hydrogen or argon. Under these conditions, the molten alloy spontaneously infiltrates the ceramic mass under normal atmospheric pressures. A solid body of the alloy can be placed adjacent a permeable bedding of ceramic material, and brought to the molten state, preferably to at least about 700° C., in order to form the aluminum matrix composite by infiltration. In addition to magnesium, auxiliary alloying elements may be employed with aluminum. The resulting composite products may contain a discontinuous aluminum nitride phase in the aluminum matrix and/or an aluminum nitride external surface layer.

Metal matrix composites

Because of their excellent mechanical properties, low density and biocompatibility, titanium foams are attractive for structural and biomedical applications. This paper reviews current techniques for titanium foam processing, which are all based on powder-metallurgy because of the extreme reactivity of liquid titanium. A first group of processes is based on powder sintering with or without place-holder or scaffolds. A second group relies on expansion of pressurized pores created during prior powder densification.

Processing of titanium foams

Handbook of Cellular Metals

Introduction Production Processes for Metal Foams Processing and Joining of Metal Foams Modelling and Simulation of Cellular Structures Characterization of Structures and Properties Applications and Industrial Uses.

Handbook of cellular metals : production, processing, applications

The deformation behaviour of different types of closed cell aluminium foam (Alulight, Alporas) was studied. Compression tests indicate that inhomogeneities in the density distribution might be the ...

Behaviour of aluminium foam under uniaxial compression

Characterization of Cellular Metals

A metal-ceramic material, comprising a heavy metal matrix containing uniformly distributed short ceramic fibers of specified aspect ratio, is new. A metal-ceramic material comprises a matrix of heavy metal (alloy), especially an iron-nickel-molybdenum or cobalt base all containing uniformly distributed short ceramic phase fibers which have a length of 5-15 times their diameter particles and which optionally having a surface layer. An Independent claim is also included for a powder metallurgical process for production of the above metal-ceramic material Preferred Features: The matrix may consist of copper or a copper alloy.

Brigitte Kriszt

Papers

Handbook of Cellular Metals

Handbook of cellular metals : production, processing, applications

Behaviour of aluminium foam under uniaxial compression

Characterization of Cellular Metals

Metal matrix fiber reinforced composite material and its preparation