IDEA #6DN9AD Nanostructured Shape Memory Alloys Elaborated By The Glass Devitrification And Powder Metallurgy Processes

APPLIED RESEARCH • NEWMATERIALS RESEARCH NANOSTRUCTURED SHAPE MEMORY ALLOYS ELABORATED BBYY THE GLASS DEVITRIFICATION AND POWDER METALLURGY PROCESSES structures use actuators to achieve a certain goal in commer(cid:2) cial applications as valves, relays, safety devices, linear motors for reasons of weight, size, cost, noiselessness, sim(cid:2) plicity. Stage ooff Development STCU and PICS projects designs are defended by publications in the international scientific journals. Contact Details Dr. Victor Kolomytsev G.V.Kurdyumov Institute for Metal Physics, National Academy of Sciences of the Ukraine; Kiev(cid:2)142, 36, Vernadskogo Blvd., Tel/Fax: (380(cid:2)44) 424(cid:2)25(cid:2)61 Mob.: 8(067) 506(cid:2)37(cid:2)67 E(cid:2)mail: kolomy@imp.kiev.ua DescriptionConventionally produced shape memory intermetallic com(cid:2) pounds with enhanced transformation temperatures are often brittle, so, non(cid:2)equilibrium processing techniques are provid(cid:2) ed for the production of amorphous precursors or nanocrys(cid:2) talline materials together with micro and macro alloying. The (TiZrHf)(NiCuMe) melt(cid:2)spun ribbons and twin(cid:2)roll strips with controlled grain size and small size dispersion have been obtained from initially amorphous state by appropriate heat treatments. Pre(cid:2)alloyed TiNi(cid:2)base powders have been obtained by the electric(cid:2)spark erosion technique providing solidification rates of 106–109K/s from liquid and vapor states. Ni(cid:2)Mn(cid:2)Ga(cid:2)X alloys powders by electric spark erosion and ultrasonic assisted severe plastic deformation by ball milling are also envisaged. Details of the processes used and enhancement of shape memory properties due to the nanoscale crystals formed from supercooled metallic liquid or broking microstructure dawn into nanostructured will be care(cid:2) fully studied on modern equipment. Innovative Aspect and Main Advantages Problem of brittleness is wide and general problem for many intermetallics, superalloys and structural alloys. Based on knowledge from the bulk metallic glasses, their exceptional ductility in supercooled liquid state (several hundreds percent of macroscopic deformation) can be used for processing of potentially brittle materials which will exhibit definite function(cid:2) al properties, i.e., shape memory, after crystallization. Recently, the partners have got experience in the development of an effective AB(cid:2)type, and potentially A3B(cid:2) and AB3(cid:2) type intermetallic alloys of specific compositions with relatively large glass forming ability in the bulk metallic precursor state by means of non(cid:2)equilibrium processes including rapid solidi(cid:2) fication techniques (planar flow casting, twin roll casting, injection casting). Superplastic deformation of the material on heating from the glassy state through the supercooled liquid region or improved plastic property of alloys with small grains have been detected on melt(cid:2)spun ribbons up to hundreds per(cid:2) cents. Another technique in which the partners are experi(cid:2) enced is the production of fine powders by electric spark ero(cid:2) sion with typical powder particle size between 10 nm and 10 ?m. Small additions of other specific elements may catalyze formation of amorphous phase. Ultrasonic assisted severe plastic deformation by ball milling for production of powders in nanocrystalline and amorphous states is available in IMP NASU. Areas ooff Application Grain size controlled shape memory alloys with high transfor(cid:2) mation temperature have high potential for use in automotive and air(cid:2)space industries in which enhanced mechanical and functional properties are required. Natural refinement of the parent phase microstructure (formation of a microcrystalline structure with small mean grain size dispersion) helps to improve the mechanical properties (to increase strength) and thus fulfill the requirement of thermoelastic phase equilibri(cid:2) um, superelasticity and shape memory accompanying martensitic transformations at increased temperatures. Today, SMA actuators are widely used to find potential solu(cid:2) tions to practical problems involving smart structures. Smart 22