Creep activation energy of flow process in Bi2Te2·8Se0·2 single crystals

Desai, C. F.; Soni, P. H.; Bhavsar, S. R.

doi:10.1007/bf02745671

Cited by 8 publications

(5 citation statements)

References 13 publications

(11 reference statements)

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“…Desai et al [17] [18]. But there are only a few reports [19,20] in the literature on the dislocation and microindentation studies of filamentary type crystals of Bi 2 Te 3-x Se x .…”

Section: Introductionmentioning

confidence: 98%

Dislocation and microindentation analysis of vapour grown Bi₂Te_3‐xSe_x whiskers

Kunjomana¹,

Chandrasekharan

2008

Cryst. Res. Technol.

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The structural defects and microhardness of Bi 2 Te 3-x Se x whiskers (x = 0, 0.2 and 0.4 at % Se) grown by physical vapour deposition (PVD) method have been investigated. Concentric pairs of dislocation loops were observed on the as-grown surfaces of short hexagonal prisms. A systematic study of dislocations in these crystals was carried out by chemical etching technique. The effects of Se doping, annealing and quenching on the mechanical properties have also been studied on the prism faces of Bi 2 Te 3-x Se x whiskers.

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“…Desai et al [17] [18]. But there are only a few reports [19,20] in the literature on the dislocation and microindentation studies of filamentary type crystals of Bi 2 Te 3-x Se x .…”

Section: Introductionmentioning

confidence: 98%

Dislocation and microindentation analysis of vapour grown Bi₂Te_3‐xSe_x whiskers

Kunjomana¹,

Chandrasekharan

2008

Cryst. Res. Technol.

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“…Sokolov et al 10 found an activation energy of plastic deformation in the range 0.5 eV to 0.75 eV for a ternary Bi 2 (Te,Se) 3 alloy during a hot-extrusion process. On the other hand, Desai et al 11 reported an activation energy value of 1.21 eV for creep phenomenon by studying the evolution of Vickers microhardness in conventional zone-melted Bi 2 Te 2.8 Se 0.2 alloy. These activation energy values are close to the values we observed for the IF background in both our extruded rod (0.59 eV) and the conventional zone-melted material with millimeter-size grains (0.95 eV) used for comparative analysis.…”

Section: Extruded Materialsmentioning

confidence: 98%

Nanostructure Characterization of Bismuth Telluride-Based Powders and Extruded Alloys by Various Experimental Methods

Vasilevskiy

Bourbia

Gosselin

et al. 2011

Journal of Elec Materi

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High-resolution transmission electron microscopy (HRTEM) observations of mechanically alloyed powders and bulk extruded alloys give experimental evidence of nanosized grains in bismuth telluride-based materials. In this study we combine HRTEM observations and x-ray diffraction (XRD) measurements, of both mechanically alloyed powders and extruded samples, with mechanical spectroscopy (MS) of extruded rods. Both HRTEM and XRD show that nanostructures with an average grain size near 25 nm can be achieved within 2 h of mechanical alloying from pure elements in an attritor-type milling machine. Residual strain orthogonal to the c-axis of powder nanoparticles has been evaluated at about 1.2% by XRD peak broadening. In contrast, XRD has been found unreliable for evaluation of grain size in highly textured extruded materials for which diffraction conditions are similar to those of single crystals, while MS appears promising for study of bulk extruded samples. Nanostructured extruded alloys at room temperature exhibit an internal friction (IF) background that is one order of magnitude higher than that of conventional zone-melted material with a grain size of several millimeters. IF as a function of sample temperature gives activation energies that are also different between bulk materials having nano-and millimeter-size grains, a result that is attributed to different creep mechanisms. Nanograin size, as well as orientation and volumetric proportion, provide valuable information for optimization of technological parameters of thermoelectric alloys and should be carefully cross-examined by various independent methods.

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“…This bonding becomes a cleavage plane that leads to strength reduction in the single crystal. To overcome the disadvantages presented by single crystals, many synthetic methods were employed to obtain Bi 2 Te 3 -based alloy bulks with higher mechanical strength and good thermoelectric properties; these methods include the Bridgman-Stockbarger method [20], equal channel angular pressing [21], hot pressing [22], hot extrusion [23,24], shear extrusion [25], and physical vapor deposition [26]. Using a two-step spark plasma sintering technique, researchers prepared textured n-type Bi 2 Te 3 with enhanced thermoelectric and mechanical properties; the authors indicated that controlling texture effectively improved the thermoelectric and mechanical properties of Bi 2 Te 3 -based materials [27].…”

Section: Bi-te Alloysmentioning

confidence: 99%

Developments in semiconductor thermoelectric materials

Chen

Zhou

et al. 2011

Front. Energy

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A surge in interest in developing alternative renewable energy technologies has been observed in recent years. In particular, thermoelectrics has drawn attention because thermoelectric effects enable direct conversion between thermal and electrical energy, and provide power generation and refrigeration alternatives. During the past decade, the performance of thermoelectric materials has been considerably improved; however, many challenges continue to exist. Developing thermoelectric materials with superior performance means tailoring interconnected thermoelectric physical parameters-electrical conductivities, Seebeck coefficients, and thermal conductivities for a crystalline system. The objectives of this paper are to introduce the recent developments in semiconductor thermoelectric materials, and briefly summarize the applications of such materials.

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Creep activation energy of flow process in Bi2Te2·8Se0·2 single crystals

Cited by 8 publications

References 13 publications

Dislocation and microindentation analysis of vapour grown Bi₂Te_3‐xSe_x whiskers

Dislocation and microindentation analysis of vapour grown Bi₂Te_3‐xSe_x whiskers

Nanostructure Characterization of Bismuth Telluride-Based Powders and Extruded Alloys by Various Experimental Methods

Developments in semiconductor thermoelectric materials

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Creep activation energy of flow process in Bi2Te2·8Se0·2 single crystals

Cited by 8 publications

References 13 publications

Dislocation and microindentation analysis of vapour grown Bi2Te3‐xSex whiskers

Dislocation and microindentation analysis of vapour grown Bi2Te3‐xSex whiskers

Nanostructure Characterization of Bismuth Telluride-Based Powders and Extruded Alloys by Various Experimental Methods

Developments in semiconductor thermoelectric materials

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Product

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Dislocation and microindentation analysis of vapour grown Bi₂Te_3‐xSe_x whiskers

Dislocation and microindentation analysis of vapour grown Bi₂Te_3‐xSe_x whiskers