نتایج جستجو برای: devitrification
تعداد نتایج: 175 فیلتر نتایج به سال:
We demonstrate the refinement and uniform distribution of the crystalline dendritic phase by friction stir processing (FSP) of titanium based in situ ductile-phase reinforced metallic glass composite. The average size of the dendrites was reduced by almost a factor of five (from 24 μm to 5 μm) for the highest tool rotational speed of 900 rpm. The large inter-connected dendrites become more frag...
Low- and high-frequency Raman experiments in the 5-200 cm(-1) and 600-1800 cm(-1) ranges were carried out in the crystalline and amorphous states of ibuprofen. Low-frequency investigations indubitably reveal the existence of a molecular disorder in the metastable phase (phase II), through the observation of quasielastic contribution below 30 cm(-1), and the absence of phonon peaks in the Raman ...
The glassy state is known to undergo slow structural relaxation, where the system progressively explores lower free-energy minima which are either amorphous (ageing) or crystalline (devitrification). Recently, there is growing interest in the unusual intermittent collective displacements of a large number of particles known as 'avalanches'. However, their structural origin and dynamics are yet ...
T he emerging field of tissue engineering has identified product storage as a significant obstacle for commercialization of products containing living cells. Traditionally employed methods of tissue banking utilize cryopreservation by freezing. Unfortunately, cryopreservation by freezing may result in loss of tissue function and viability by several recognized mechanisms of which ice formation ...
Possible relationships between measures of glass stability (GS) against devitrification on heating (evaluated by the Hrub€y parameter KH 1⁄4 ðT h c TgÞ=ðTm T h c Þ, and the parameter Kw 1⁄4 ðT h c TgÞ=TmÞ and a criterion of glass-forming ability (GFA) – the critical cooling rate – were investigated by computing non-isothermal crystallization for typical values of the main quantities that contro...
In this work we report on an ultrashort pulsed laser annealing-driven devitrification of thin film Cu67Zr33 metallic glass characterized by micro-beam X-ray diffraction and electron microscopy techniques. The essential feature annealing is ultrafast heating (1014 K/s) femtosecond optical excitation followed extremely rapid cooling (1010–12 due to heat dissipation into the substrate. During repe...
This work presents the results of a study focused on the development of forsterite-nepheline glass-ceramic with the use of rice husk ash (RHA) as a silica source. The glass-ceramics were produced by a sintering process of a glassy frit formulated in the MgO-Al2O3-SiO2 base system with the addition of B2O3 and Na2O to facilitate the melting and pouring processes. The crystallisation study was ca...
While lots of measurements describe the relaxation dynamics of the liquid state, experimental data of the glass dynamics at high temperatures are much scarcer. We use ultrafast scanning calorimetry to expand the timescales of the glass to much shorter values than previously achieved. Our data show that the relaxation time of glasses follows a super-Arrhenius behaviour in the high-temperature re...
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