Methods of laboratory of strength and plasticity

ISSPMT
Institute of Solid State Physics, Materials Science and Technologies
NAS of Ukraine

Methods of laboratory of strength and plasticity

The implementation of large plastic deformations (including cryogenic conditions)by methods of quasihydroextrusion, rolling, drawing and their combination

Creation in metals and alloys of nanometer-scale structures

Dependence of the average cell size on the degree of deformation by rolling at various temperatures:
Т=300 К (1),
77 К (2),
20 К (3) и 4,2 К (4).

Cell size distribution in Zr, strained by rolling at 300 K (e = 3,9)

Characteristics of nanostructured samples Zr and Zr1Nb

Material	D,nm	N_d, cm² Dislocation density	C_v 10²Volume density of boundaries
Zr	82	3.4x10¹⁰	4.3
ZrlNb	61	1.5x10¹¹	3.4

Effects of Hardening

Additional hardening of austenitic steel at a different strain epures

Additional hardening austenitic steel as a result of combined deformation under cryogenic conditions

Microhardness of 18Cr10NiTi steel on the degree deformation by drawing at 77 K (1),
quasihydroextrusion at 77 K (2)
and their combination (3);
e1 and e2 - fraction of deformation by quasihydroextrusion and drawing, respectively.

Increase the strength characteristics of austenitic steel as a result of large cryogenic deformation by quasihydroextrusion

Yield strength steel 18Cr10NiTi vs strain by quasihydroextrusion at 300 K (1), 77 K (2) K and 20.4 K (3).

St50 steel samples strained by cryogenic quasihydroextrusion without back pressure (a) and using the back pressure (b).

Microstructure (a) and electron diffraction pattern (b) of steel 18Cr10NiTi after quasihydroextrusion at 77 K by 45% and subsequent annealing at 750 K.

Mechanical testing in tension and compression at temperature range 4,2….1000 к

Chromium embrittlement at low temperatures.
Temperature dependences of the yield stress σ_Т and strain of brittle fracture σ_f (dashed line) the single-crystal chromium of orientation.

The microstructure of the fracture surface of alloy Cr-V (a) and a single crystal of Cr (b) in the ductile-brittle transition region.

The magnetic and ultrasonic treatment of constructional and functional materials

Relaxation effects in structural materials resulting magnetic and ultrasonic exposures

Increase of impact toughness and a decrease of temperature ductile-brittle transition for weld joint vessel steel as a result of exposure alternating magnetic field

Temperature dependences of impact toughness of steel 15Kh2NMFA (1), weld joint before magnetic treatment (2), and after treatment (3).

Increase of impact toughness vessel steel 15Kh2NMFA as a result of ultrasonic treatment

Temperature dependence of impact toughness of the steel in the initial state (1) and after ultrasonic treatment (2).

Change in the microhardness of nanostructured alloy Zr-2.5Nb due to ultrasonic treatment

Нμ vs τ for σ_us=200 MPa (1) and σ_us=85 MPa (2).

Relaxation effects in functional materials due to ultrasonic treatment

Enhance of mechanical stability of metal-oxide compound YBaCuO

Dependence of the yield strength on the us treatment duration: 1 - Т_US = 373 К; 2 - Т_US = 573 К.

Enhance of critical currents of technical superconductors

Field dependences of the critical current density of multi filamentary (n = 55) superconducting wire based on Nb₃Sn: the initial state (1),
after us treatment at 300 K (2)
and 77 K (3).

Creep in the temperature range 4,2…..700 К

Structural instability and effects of magnetic treatment in changing the creep rate of the irradiated vessel steel

Dependences of the creep rate at T = 600 K from stress for vessel steel:
1 – initial state;
2 - electron irradiation of E=10 MeV, D = 5 × 10¹⁹ cm^-2;
3 - irradiation + magnetic treatment (H = 700 E, f=50 Hz, t=2 hrs.);
4 - irradiation + magnetic treatment (H = 700 E, f=50 Hz,t=3 hrs.);
5 - irradiation + magnetic treatment in pulsed regime.

Influence of mechanical-thermal treatment on the creep of zirconium

Dependences of the creep rate at T = 300 K (1,2,3) and 700 K (4,5,6) from stress for zirconium:
1,4 - after rolling at 300 K, e = 2.5 and annealing at 800 K;
2,5 - after rolling at 300 K, e=2.5 and quenching;
3,6 - after rolling at 100 K, e=2.5 and annealing at 800 K.

Fatigue in the temperature range 4,2…..400 К

Effect of test temperature on the low-amplitude fatigue of Zr and alloy Zr1Nb

Fatigue curves of alloy Zr1Nb (1, 2) and Zr (3,4) at 293 K (1,3) and 77 K (2,4)

The structure of the surface near the place of the specimen fracture from the alloy Zr1Nb after fatigue tests at 293 K with a stress amplitude σ_а = 500 MPa

Measurement of low-frequency internal friction and elastic modules in the temperature range of 4,2…..1000 К

Decomposition into the peaks of experimental curves of internal friction ultrafine-grained (UFG) titanium alloy VT6 strained by rolling at 77 K

Temperature dependence of the damping decrement.

Decrease in shear modulus of the titanium alloy VT6 as a result of cryogenic (77 K) deformation

Temperature dependences of the shear modulus:
1 - UFG condition;
2 - after rolling by 42%;
3 - after rolling by 60%;
4 - after quasihydroextrusion by 20%.

Measurement of electrical resistivity in the temperature range 4,2….700 К and calculations of microscopic parameters of metals. metallography and transmission microscopy

Microstructure of strained chromium single crystal.
Crack nucleation at the intersection of twins (a);
stop of a crack at twin boundary (b);
and at encounter with the other crack (c);
stress relaxation in the crack mouth by twinning (d);
and sleep (e).

Twins (a) and microtwins (b)in zirconium strained at 4.2 K

The effective microscopic characteristics of Nb and Ta in different structural states which was calculated using the parameters of temperature dependence of electrical resistivity:
λ - electron-phonon coupling constant;
Ω_р – plasma frequency,
V_F – Fermi velocity,
N(0) – the density of states,
z – reduced frequency of collisions

Material	α	Ω _p, eV	V_F, 10⁸cm/s	N(0), state/eV∙atom	z
Pure Nb	1,148	9,32	0,663	1,357	0,204
Nb with impurities	1,133	9,83	0,728	1,237	1,127
Deformed Nb	1,181	8,65	0,588	1,533	1,404
Pure Nf	0,817	8,12	0,611	1,216	0,064
Ta with impurities	0,804	8,16	0,627	1,191	1,183

Measurement of critical parameters of superconductors in different structural states

Critical currents of technical superconductors based on Nb₃Sn under tensile loads.
J_с changes of multifilamentary (n = 7225) wire composite under strain (1) and in the unloaded condition (2)

Change in the critical currents of the superconductor Nb-Tias a result of annealing at 670 K.
J_c (H=5 T, T=4.2 K) vs Τ for Nb-Ti samples strained by drawing at 300 (1) and 77 K (2).

Correlation of critical current density and normal current component for monatomic type II superconductors

Dependences corresponding to viscous flow of the vortex lattice for Nb with a high (~10¹¹cm^-2) density dislocations:
а – normal component of current J₁ (1) and critical current J_c (2) vs reduced induction;
b - б J₁/J_c vs b.