摘要:

AbstractThe amplitude dependence of ultrasound absorption due to dislocations, α, has been studied for single crystals of pure lead and indium as well as for lead doped with Tl, Sn or Bi, both in the superconducting and normal state and for a wide range of ultrasound amplitudes, ε0. Pure and Tl‐doped superconducting lead at large ε0displayed a maximum on the α(ε0) dependence which became a plateau upon transition to the n‐state. This is direct evidence for a change from static to dynamic dislocation hysteresis as a result of the increase in the electron drag constant. Limit values for the dislocation loop lengths have been estimated, viz. 2.4 × 10−4cm

ISSN:0232-1300    

DOI:10.1002/crat.2170190802

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractThe effect of the superconducting transition on the flow stress in single and polycrystals of Pb‐In and Pb‐Sn alloys has been studied in the temperature range 1.8 K toTe. Unlike earlier efforts, these experiments involved investigation of the magnetic flux trapping. Two types of temperature dependences of the magnetic flux trapping,B0(T), were revealed. In Pb‐1.9 at.% In and Pb‐6 at.% Sn alloys (subjected to various thermal treatment),B0monotonically rises with lowering temperature. In Pb‐1.8, 3 at.% Sn single crystals the flux trapping arises at high strains (>50%) and low temperatures (<2.5 K). In this caseB0magnitude depends on the strain rate. The difference in theB0(T) behaviour is associated with dissimilar flux pinnig by pinning centres. The date onB0(T) obtained give an insight into the two types of the Δσ(T) dependences; taking into account of the flux trapping allowed the Δσ values to be corrected, so that as a result, a single ΔσSN(T) curve was obtained for all the alloys and str

ISSN:0232-1300    

DOI:10.1002/crat.2170190803

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractThe results of acoustic studies of elasticity and dislocation inelasticity of crystals are presented. Regularities of elastic anisotropy variation with ionicity of bonds in ANB8‐Ncrystals have been considered. Amplitude dependences of ultrasound damping supply the information on dislocation structure and dislocation — to point defect interaction. Oscillation of dislocations during internal friction measurements are compared to their translation motion at the onset of plastic f

ISSN:0232-1300    

DOI:10.1002/crat.2170190804

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractAmplitude and temperature spectra of ultrasound absorption in weakly deformed high purity molybdenum single crystals of different orientations were measured. The results were discussed in terms of parameter changes related to quasiparticle‐ or dislocation oscillations, respectively, dislocation‐point defect interactions as well as defect generation at microplastic deformat

ISSN:0232-1300    

DOI:10.1002/crat.2170190805

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170190806

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractThe value of the trapped magnetic flux in strained superconducting alloys Pb‐Ni and Pb‐Sn during n‐s transitions is measured and the correction is made of the obtained earlier on these alloys temperature and deformation dependences of the softening effect, stimulated by the superconducting transition. The peculiarities of the behaviour of the true softening effect on the mentioned dependences and physical nature of these peculiarities are disc

ISSN:0232-1300    

DOI:10.1002/crat.2170190807

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170190808

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractThe branch of studies of work‐hardening and the related structural states as yet has not been developed sufficiently. This paper touches upon the problem of work‐hardened state formation by a dislocation forest and its stability against a range of infiuen

ISSN:0232-1300    

DOI:10.1002/crat.2170190809

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractAn arrangement for measuring the thermoelectric voltage (Seebeck signal) during the crystal growth from a liquid zone is described. Using the example of growing PbTe single crystals by THM it is shown that different equilibrium temperatures at both phase boundaries provide a differential Seekeck voltage depending on the crystal growth rate. Relaxation times which are needed to reach steady‐state conditions with respect to the concentration difference between the growing and solving interface in the case of a start or sudden stop of the heater motion can be obtaine

ISSN:0232-1300    

DOI:10.1002/crat.2170190810

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractThin films of CuInTe2, CuInSe2, CuInS2, CuGaSe2and CuGaS2were deposited onto (111)‐and (100)‐oriented CaF2substrates by flash evaporation technique. Epitaxial growth occurs at substrate temperatures in the range from 750 to 900 K, dependent on the kind of film material. Contrary to the case of GaAs, GaP and Ge substrates there are always polycrystalline parts. The layers were found to be single phase and crystallizing in the chalcopyrite structure only. The composition of the films varied in dependence on the substrate temperature. In the range of about 700 K a nearly stoichiometric composition was fo

ISSN:0232-1300    

DOI:10.1002/crat.2170190811

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY