The influence of mechanical stress on the structural phase transitions in V 3 Si and Nb 3 Sn

Self Cite

Lattice parameters of specimens deformed plastically at high temperatures are determined between 7 and 293 K. Above and below the well known phase transition temperature of non‐deformed crystals tetragonal and rhombic symmetry is detected after deformation, respectively. The results agree qualitatively with the temperature dependence of lattice parameters calculated for V3Si single crystals under uniaxial pressure. Dislocations created by plastic deformation appear to have the same effect.

Section: Discussionmentioning

confidence: 99%

“…Fig. 7 shows the theoretical temperature dependence of lattice parameters near the lattice transition temperature calculated by using the results of [8].…”

Section: Discussionmentioning

confidence: 99%

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On the lattice transformation in plastically deformed V3Si single crystals studied by the Kossel technique

Ullrich

Reinhold

Däbritz

et al. 1978

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“…I n Fig. 6 the radial stress a,,, the axial stress a,,, and the hydrostatic pressure ' I n the absence of external stress the axial stress in the core is twice as large as the radial stress according to (21). With increasing external tension hydrostatic conditions are realized in the core a t the external stress T * =c ,~, the corresponding hydro-p q 0 Fig.…”

Section: Stress and Strain In A Composite Conductormentioning

confidence: 96%

“…6. Stress tensor components in the core of the composite conductor as function of an applied tensile stress, according to (20) and (21). At the tension t* there are hydrostatic conditions in the core…”

Section: Stress and Strain In A Composite Conductormentioning

confidence: 99%

Effect of non-hydrostatic stress on the superconducting transition of A15 compounds with high critical temperature

Pietrass

1980

Self Cite

The influence of the anomalous elastic behaviour of A15 compounds (e.g. Nb3Sn and V3Si) on its superconducting transition is investigated theoretically. The sensitive reaction of the superconducting properties to uniaxial stress is explained as a consequence of the elastic softening. In single crystals the change of the transition temperature depends strongly on the direction of the applied uniaxial stress. In polycrystals the width of the transition curve increases quadratically with the uniaxial stress. The shape of the broadened transition curve is calculated approximately. In a composite conductor the A15 layer is exerted to a non‐hydrostatic stress as a result of different thermal expansion coefficients. The present model explains the observed parabolic strain dependence of superconducting properties in Nb3Sn composite conductors and allows to estimate the strain at which damage of the A15 layer occurs.

Linear thermal expansion of SrTiO3

Tsunekawa

Watanabe

Takei

1984

The linear thermal expansion of SrTiO3 in the temperature range 10 to 150 K is measured with a relative accuracy of 5 × 10−7 by using a three‐terminal capacitance dilatometer. The dilation δL/L of a single‐domain crystal is converted to the ratio of the pseudo‐cubic cell constants a(T)/a(Ta) by the equation a(T)/a(Ta) = (1 + (δL/L) T}/{1 + (δL/L)Ta}, where L is the specimen length, Ta is the cubic‐to‐tetragonal transition temperature and T ≦ T,. The present a(T)/a(Ta) curve shows a coincidence with the temperature dependence of cos φ between 40 and 108 K, and reveals a clear difference with it below 40 K, where. φ is the rotation angle of the TiO6 octahedra around the [001] axis. The temperature at which the dilation shows a minimum, 37.5 K, is very close to the transition point Tc = (32 ± 5) K predicted by Cowley.