Aging kinetics of levoglucosan orientational glass as a rate dispersion process and consequences for the heterogeneous dynamics view

2016 ◽  
Vol 145 (5) ◽  
pp. 054501 ◽  
Author(s):  
Maria Cristina Righetti ◽  
Elpidio Tombari ◽  
G. P. Johari
2021 ◽  
Vol 126 (9) ◽  
Author(s):  
Nafisa Begam ◽  
Anastasia Ragulskaya ◽  
Anita Girelli ◽  
Hendrik Rahmann ◽  
Sivasurender Chandran ◽  
...  

Author(s):  
E.N. Kablov ◽  
◽  
E.V. Belov ◽  
A.V. Trapeznikov ◽  
A.A. Leonov ◽  
...  

Based on the conducted research, it has been found that quenching with hot isostatic pressure and step-by-step aging with consistently increasing temperatures of low-temperature aging (first stage) and high-temperature aging (second stage) provides high tensile strength for AL4MS copper silumin during cold box casting, increases the flow stress by 10%, and maintains high plasticity compared to the level of properties after single-stage aging.


2003 ◽  
Vol 43 (9-11) ◽  
pp. 1785-1790
Author(s):  
P. Soussan ◽  
G. Lekens ◽  
R. Dreesen ◽  
W. De Ceuninck ◽  
E. Beyne
Keyword(s):  
Ex Situ ◽  

2021 ◽  
Author(s):  
Saikat Das ◽  
R. Govinda Rao ◽  
Prasanta Kumar Rout

Abstract In the present work, the artificial aging kinetics of SiCp particles reinforced AA7075-SiCp composite fabricated by stir casting method was investigated. The aging behavior of AA7075-SiCp composite was investigated by Rockwell hardness tests and differential scanning calorimetry (DSC). Results show there are no changes in the sequences of formation and dissolution of precipitate. Reinforced particles are uniformly distributed throughout the matrix. The hardness profile shows increase in hardness with the comparison of AA7075 base alloy. In addition to SiCp in the matrix, precipitation kinetics has changed compared with base alloy since higher dislocations present in composite, hence requires lower activation energy to form ή precipitate and takes less time to reach the maximum hardness. In contrast, the addition of SiCp at low volume percent also showing accelerated aging phenomena in the composite during the aging process. High-resolution transmission electron microscope (HRTEM) micrograph of peak age (T6) condition divulges that enormous fine and plate-like ή (MgZn2) precipitates are uniformly distributed in the composite.


1995 ◽  
Vol 68 (5) ◽  
pp. 836-841 ◽  
Author(s):  
Qi Li ◽  
D. L. Feke ◽  
I. Manas-Zloczower

Abstract The dispersion of carbon black agglomerates in poly(dimethyl siloxane) (PDMS) has been studied experimentally. Both the structure of carbon black aggregates comprising the agglomerate and the presence of the matrix within the agglomerate were found to affect the mode of dispersion, critical stress conditions, and the kinetics of the dispersion process. Agglomerates of high structure carbon black are generally more difficult to disperse than agglomerates of low structure carbon black at the same agglomerate density. Depending on the degree of saturation of the agglomerate by PDMS, the dispersion process may be either enhanced or retarded compared to the dry state.


2018 ◽  
Vol 941 ◽  
pp. 863-868
Author(s):  
Robert E. Hackenberg ◽  
Megan G. Emigh ◽  
Pallas A. Papin ◽  
Ann M. Kelly ◽  
Robert T. Forsyth ◽  
...  

Overall kinetics of lamellar overaging reactions in U-5.5Nb and U-7.5Nb were analyzed by Avrami-Arrhenius analyses of volume fractions measured from an extensive temperature-time (T-t) matrix of specimens. The cellular initiation site (grain boundaries, inclusions) and regimes of lamellar divergency-cum-slowing growth rate were explicitly accounted for. Avrami exponents n from T-t regimes of constant-growth rate were consistent with theory (1<n<3); those from divergent T-t regimes were smaller, n~0.7, which is not surprising given their different growth rate behavior. The apparent activation energies Q were similar for grain-boundary and inclusion-nucleated discontinuous precipitation, indicating that their nucleation site does not alter their overall kinetics. Avrami Analysis of Isothermal Aging Kinetics


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