Functional Graded Structures:

Gradient of physic-mechanical or chemical-biological characteristics under layer-by-layer SLS could be organized via changing of sintering depth (when turning from layer to layer), computer simulation of internal structure (types of connectivity) for the powdered compositions, or simply via mixture changing powdered compositions. Below the examples of experimental realization, described above decision, are presented:

Fig. a) and b) Type of connectivity equal 2-2.

Types of connectivity

Fig. b) Type of connectivity is 3-3, Fig d) Type of connectivity is 3-1.

On the base of our patents about metal - polymer powdered compositions (patent of RF N 2145269) the filter elements were created (patent of RF N 2212982), possessing unique features by flow selectivity and permeability.

Gradient of properties could realized as by mean of CAD, as sintering regime selection, also:

Flow structure in porous filter could be realized on the CAD in MPC	“Strips” correspond different degrees of permeability	Density of sintered layers are changed from layer to layer (nitride titanium)

There is exists possibility of catalytic characteristic governing in the filter elements (patent of RF N 2188709). We have been shown possibility of selective management of catalytic properties of filter elements (patent RF N 2188709) by means of meso- (nano-) additive of the next metal oxides (Al₂2O₃, TiO₂, NiO₂) in the synthesized layer-by-layer filter elements. Arrays of applications of porous meso- (nano-) structures are very spread:

1. Elements of gas - / hydro- separating systems;
2. Throttling elements;
3. Oscillation absorber of pressure and noise cancellation device;
4. Porous fuel cells and catalysts;
5. Temperature stabilized circuits ;
6. Porous systems of mixture and sputtering.

One more perspective direction of porous meso- structures application is the membranous technologies, catalytic inserts and creation of dosimeters for a pharmaceutical industry.

Gradient of piezo properties could be realized in the PZT ceramics:

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Laser marking of rubber PZT ceramic (left- combine with Rostov Univ.) and 0-3 type connectivity of structure PZT+SiO₂ (right).

Possibilities of SL-Synthesis of FG- structures based on nitinol and titanium:

SLS was carried out at Ar, and fabricated 3D parts "cube type" 100x100 points /10x10 mm/ (each cube has 20 layers), laser scan velocity was v = 2,8 cm/s, laser power - 30 W. NiTi (Polema graded), titanium (PTC graded), titanium with nickel cladding coating (NiTi₂-phase), NiTi (first layer always) were used, material interchanged from layer to layer; the depth of layer ~280 mk. Below it is shown the lamination and gradient of properties in the synthesized 3D parts.

Appearance

Micrograph (optic metallography)

Microanalysis (optic metallography)

Ti+NiTi
Ti+Ti2Ni cladding

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