UST logo IPBT logo Part logo
Institute of Industrial and Business Technologies
Ukrainian State University of Science and Technologies

Research directions

Modifying TECHNOLOGY of Constructional and piston ALLOYS of Al-Si SYSTEM 

The new ecologically clean modification technology of silumins with ways of outfurnace treatment of melt for reception cast with the high mechanical and operational characteristics is offered

 

The technology provides preparation and input in an alloy an alloying composition for modification with previous and subsequent treatment of an alloy before filling.

The modifying effect is kept within 6 hours after input alloying composition that considerably improves work and expands technological opportunities of process in comparison with other modifications.

The technology provides reception high-quality casts, capable to work under hydro- and pneumoloadings in various environments at existing kinds of casting in chill mould and sand-clay mould.

The mechanical properties of alloys are stable and make: σВ=280÷340 МPа, σ0,2=220÷320 МPа, δ=6÷10 % for constructional alloys and 70-85 НВ for piston silumins.

Cast body a complex configuration with a wall by thickness 8…9 mm hold by hydrostatic pressure before destruction within the limits of 350÷380 МPа.

The technology guarantees preservation of necessary quantity of the basic modifying element during possible repeated remeltings.

Nonconventional ways of melt outfurnace treatment provides:

- additional grinding of primary crystals of a silicon solid solution and formation of thin-dissociated eutectic;

- economy of elements - modifiers in 1,5-2,0 times;

- reception of stable properties in different thickness sections cast a complex configuration;

- increase of strong properties on 30-40 % and plasticity in 1,5-2,0 times in comparison with alloys which are not subjected outfurnacetreatment.

 

New technology of production "solar" silicon with increased electrophysical properties

The technology provides:

- increase of "solar" silicon monocrystals life-time of nonbasic charge bearers (τNCB) from 18,4 μs up to 228 μs at the expense of purposeful alloying;

- additional increase of "solar" silicon plates life-time of nonbasic charge bearers (τNCB) in 1,5-2 times in comparison with monocrystals at the expense of heat-treatment;

- increase of “solar” batteries efficiency up to 21 %.

 

Developed:

- physicochemical modelling technique for selection effective alloying elements for semiconductor silicon, which considers a change of  interaction energy of silicon atoms in the crystal lattice;

- choice of temperatures, heating-cooling speed under technological procedures (impurities diffusion, gettering, annealing) was carried out with purpose to avoid phase transformations in silicon, formation defect structure and electrophysical properties degradation;

- regims for heat-treatment of monocrystals and alloyed silicon plates, taking into account the temperatures of phase transformations.

The technology is intended for reception of mechanical engineering products (rolls, mills spheres) from high chromium iron–carbon alloys (where carbon and chromium content is 3–3,5% and 12–21,5% accordingly) with the nanostructurematrix (thickness of the α-phase bainite plate an makes 20-30 nm) at the expense of realization of bainite transformation during cooling products from foundry heating.

The technology provides:

- reduction of the charge expensive alloying elements: chromium - on 24%, nickel - on 50%, titanium, vanadium, tungsten - on 100%;

- increase of wear resistance of details in 1,5-2 times;

- increase of heat resistance in 1,5 times;

- increase of service life of details in 2-3 times.

Is developed:

- the isothermal and thermokinetics diagram of austenite decomposition are constructed in iron–carbon alloys with 12-21% of Сr;

- the critical temperatures Ас1, Асm, МB are determined depending on the content of chromium, alloying elements and cooling speed at crystallization;

- the regimes of heat treatment with isothermal soaking in area of bainite transformation for concrete products are developed.

The regimes of heat treatment are protected by the patents of Ukraine (the declaration patent 59272 A; the declaration patent 69795 A).

 

 

            

 



Uplink: Scientific activities