Role of Interfacial Dislocation Networks During Secondary Creep at Elevated Temperatures in a Single Crystal Ni-Based Superalloy

2021 ◽  
Author(s):  
Yawei Li ◽  
Li Wang ◽  
Yufeng He ◽  
Wei Zheng ◽  
Langhong Lou ◽  
...  
Keyword(s):  
Single Crystal ◽  
Elevated Temperatures ◽  
Secondary Creep ◽  
Interfacial Dislocation

Role of oxygen in surface kinetics of SiO2 growth on single crystal SiC at elevated temperatures

2021 ◽  
Vol 47 (2) ◽  
pp. 1855-1864
Author(s):  
Yongjie Zhang ◽  
Shaoxiang Liang ◽  
Yi Zhang ◽  
Rulin Li ◽  
Zhidong Fang ◽  
...  
Keyword(s):  
Single Crystal ◽  
Elevated Temperatures ◽  
Surface Kinetics ◽  
Single Crystal Sic ◽  
Kinetics Of

Growth of Epitaxial CoSi2 Through a Thin Interlayer

1996 ◽  
Vol 427 ◽  
Author(s):  
R. T. Tung
Keyword(s):  
Thin Films ◽  
Aqueous Solution ◽  
Thin Layer ◽  
Single Crystal ◽  
Epitaxial Growth ◽  
Elevated Temperatures ◽  
Time Process ◽  
Thin Interlayer ◽  
Technological Interest

AbstractThe phenomenon of Ti-interlayer mediated epitaxy (TIME) of CoSi2 on Si(100) has attracted much academic and technological interest. As yet, the role of the interlayer, Ti, is not fully understood. The various drawbacks of the TIME process have driven the search for a better interlayer. New results are presented which demonstrate the efficacy of a thin SiOx layer, grown in a peroxide-containing aqueous solution, in inducing nearly perfect epitaxial growth of CoSi2 on practically all surfaces of Si. This technique, dubbed oxide mediated epitaxy (OME), allows a thin layer of epitaxial CoSi2 to grow sub-surface, leaving the SiOx layer largely on the surface of the silicide. An interesting result of the surface oxide cap is a significant re-evaporation of cobalt observed during deposition at elevated temperatures. Thicker (10-30nm), excellent quality, CoSi2 single crystal thin films have been grown by repeated growth sequences on Si(100), (110), (211) and (511). Nearly perfect type A oriented CoSi2 layers were grown on Si(111) using mixed A/B oriented template layers.

Mechanical Properties and Dislocation Structure of Single Crystal Cdte Deformed in Compression at 300°C

1976 ◽  
Vol 34 ◽  
pp. 592-593
Author(s):  
Ernest L. Hall ◽  
J. B. Vander Sande
Keyword(s):  
Mechanical Properties ◽  
Single Crystal ◽  
Dislocation Structure ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Strain Curve ◽  
Optical Devices ◽  
Semiconductor Compound ◽  
Wide Range ◽  
Sample Orientation

The present paper describes research on the mechanical properties and related dislocation structure of CdTe, a II-VI semiconductor compound with a wide range of uses in electrical and optical devices. At room temperature CdTe exhibits little plasticity and at the same time relatively low strength and hardness. The mechanical behavior of CdTe was examined at elevated temperatures with the goal of understanding plastic flow in this material and eventually improving the room temperature properties. Several samples of single crystal CdTe of identical size and crystallographic orientation were deformed in compression at 300°C to various levels of total strain. A resolved shear stress vs. compressive glide strain curve (Figure la) was derived from the results of the tests and the knowledge of the sample orientation.

scholarly journals Creep Damage Repair of a Nickel-Based Single Crystal Superalloy Based on Heat Treatment

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 623
Author(s):  
Xiaoyan Wang ◽  
Meng Li ◽  
Yuansheng Wang ◽  
Chengjiang Zhang ◽  
Zhixun Wen
Keyword(s):  
Heat Treatment ◽  
Single Crystal ◽  
Creep Damage ◽  
Primary Creep ◽  
Single Crystal Superalloy ◽  
Secondary Creep ◽  
Creep Life ◽  
Phase Coarsening ◽  
Damage Repair ◽  
Creep Time

Taking nickel-based single crystal superalloy DD6 as the research object, different degrees of creep damage were prefabricated by creep interruption tests, and then the creep damage was repaired by the restoration heat treatment system of solid solution heat treatment and two-stage aging heat treatment. The results show that with the creep time increasing, the alloy underwent microstructure evolution including γ′ phase coarsening, N-type rafting and de-rafting. After the restoration heat treatment, the coarse rafted γ′ phase of creep damaged specimens dissolved, precipitated, grew up, and became cubic again. Except for the specimens with creep interruption of 100 h, the γ′ phase can basically achieve the same arrangement as the γ′ phase of the original sample. The comparison of the secondary creep test shows that the steady-state creep stage of the test piece after the restoration heat treatment is relatively increased, and the total creep life can reach the same level as the primary creep life. The high temperature creep properties of the tested alloy are basically recovered, and the restoration heat treatment effect is good.

scholarly journals Modeling of magneto-conductivity of bismuth selenide: a topological insulator

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Yogesh Kumar ◽  
Rabia Sultana ◽  
Prince Sharma ◽  
V. P. S. Awana
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Single Crystal ◽  
Single Crystals ◽  
X Ray Diffraction ◽  
Field Range ◽  
X Ray ◽  
Bulk Carriers ◽  
Different Temperatures

AbstractWe report the magneto-conductivity analysis of Bi2Se3 single crystal at different temperatures in a magnetic field range of ± 14 T. The single crystals are grown by the self-flux method and characterized through X-ray diffraction, Scanning Electron Microscopy, and Raman Spectroscopy. The single crystals show magnetoresistance (MR%) of around 380% at a magnetic field of 14 T and a temperature of 5 K. The Hikami–Larkin–Nagaoka (HLN) equation has been used to fit the magneto-conductivity (MC) data. However, the HLN fitted curve deviates at higher magnetic fields above 1 T, suggesting that the role of surface-driven conductivity suppresses with an increasing magnetic field. This article proposes a speculative model comprising of surface-driven HLN and added quantum diffusive and bulk carriers-driven classical terms. The model successfully explains the MC of the Bi2Se3 single crystal at various temperatures (5–200 K) and applied magnetic fields (up to 14 T).

Oxide Mediated Epitaxial Growth of CoSi2 in a Single Deposition Step

1999 ◽  
Vol 564 ◽  
Author(s):  
S. Ohmi ◽  
R. T. Tung
Keyword(s):  
Single Crystal ◽  
Epitaxial Growth ◽  
Diffusion Barrier ◽  
Blocking Layer ◽  
Deposition Step

AbstractA number of modifications of the oxide-mediated epitaxy (OME) technique are presented which have enabled the growth of thick (∼25–40nm) epitaxial CoSi2 layers in a single deposition sequence. The uses of (a) a thin Ti cap, (b) a thin Ti blocking layer, (c) the codeposition of Co-rich CoSix, and (d) the co-deposition of Col−xTix. have all been shown to lead to improved epitaxial quality over the pure Co OME process, for Co thickness greater than 6nm. Essentially uniform, single crystal silicide layers of over 25nm have been grown in a single deposition step. These results are supportive of the proposed role of a diffusion barrier/kinetics retarder on the part of the interlayer in the OME and the Ti-interlayer mediated epitaxy processes.

scholarly journals The cAMP-PKA Pathway Regulates Growth, Sexual and Asexual Differentiation, and Pathogenesis in Fusarium graminearum

2014 ◽  
Vol 27 (6) ◽  
pp. 557-566 ◽  
Author(s):  
Shuai Hu ◽  
Xiaoying Zhou ◽  
Xiaoying Gu ◽  
Shulin Cao ◽  
Chengfang Wang ◽  
...  
Keyword(s):  
Fusarium Graminearum ◽  
Vegetative Growth ◽  
Double Mutant ◽  
Elevated Temperatures ◽  
Hyphal Growth ◽  
Growth Defects ◽  
Plant Infection ◽  
Dependent Protein ◽  
Pka Pathway

Like many other filamentous ascomycetes, Fusarium graminearum contains two genes named CPK1 and CPK2 that encode the catalytic subunits of cyclic AMP (cAMP)-dependent protein kinase A (PKA). To determine the role of cAMP signaling in pathogenesis and development in F. graminearum, we functionally characterized these two genes. In addition, we generated and characterized the cpk1 cpk2 double and fac1 adenylate cyclase gene deletion mutants. The cpk1 mutant was significantly reduced in vegetative growth, conidiation, and deoxynivalenol production but it had increased tolerance to elevated temperatures. It was defective in the production of penetration branches on plant surfaces, colonization of wheat rachises, and spreading in flowering wheat heads. Deletion of CPK1 had no effect on perithecium development but the cpk1 mutant was defective in ascospore maturation and releasing. In contrast, the cpk2 mutant had no detectable phenotypes, suggesting that CPK2 contributes minimally to PKA activities in F. graminearum. Nevertheless, the cpk1 cpk2 double mutant had more severe defects in vegetative growth and rarely produced morphologically abnormal conidia. The double mutant, unlike the cpk1 or cpk2 mutant, was nonpathogenic and failed to form perithecia on self-mating plates. Therefore, CPK1 and CPK2 must have overlapping functions in vegetative growth, differentiation, and plant infection in F. graminearum. The fac1 mutant was also nonpathogenic and had growth defects similar to those of the cpk1 cpk2 mutant. However, deletion of FAC1 had no effect on conidium morphology. These results indicated that CPK1 is the major PKA catalytic subunit gene and that the cAMP-PKA pathway plays critical roles in hyphal growth, conidiation, ascosporogenesis, and plant infection in F. graminearum.

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