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J.c. Qiao - One of the best experts on this subject based on the ideXlab platform.
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dynamic Mechanical Relaxation behavior of zr35hf17 5ti5 5al12 5co7 5ni12cu10 high entropy bulk metallic glass
Journal of Materials Science & Technology, 2021Co-Authors: Liuchao Zhang, Eloi Pineda, J M Pelletier, Daniel Crespo, Y J Duan, Takeshi Wada, Hidemi Kato, J.c. QiaoAbstract:Abstract Non-equiatomic high entropy bulk metallic glasses were reported recently and show unique Mechanical and physical properties. Dynamic Mechanical Relaxation behavior of Zr35Hf17.5Ti5.5Al12.5Co7.5Ni12Cu10 high entropy bulk metallic glass was investigated by dynamic Mechanical analysis (DMA) and the Mechanical spectra could be well described by the quasi-point defects (QPD) theory. Compared to typical metallic glasses, the intensity of the β Relaxation of Zr35Hf17.5Ti5.5Al12.5Co7.5Ni12Cu10 high entropy bulk metallic glass is lower due to the sluggish diffusion. At the same time, the correlation factor χ is higher than that of conventional metallic glasses and this is ascribed to the high configuration entropy. In parallel, physical aging below the glass transition temperature leads to a decrease of atomic mobility, caused by a decrease of the concentration of defects.
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dynamic Mechanical Relaxation and thermal creep of high entropy la30ce30ni10al20co10 bulk metallic glass
Science China-physics Mechanics & Astronomy, 2021Co-Authors: Langting Zhang, Eloi Pineda, J M Pelletier, Daniel Crespo, Y J Duan, Yunjiang Wang, J.c. QiaoAbstract:Dynamic Mechanical Relaxation is a fundamental tool to understand the Mechanical and physical properties of viscoelastic materials like glasses. Mechanical spectroscopy shows that the high-entropy bulk metallic glass (La30Ce30Ni10Al20Co10) exhibits a distinct β-Relaxation feature. In the present research, dynamic Mechanical analysis and thermal creep were performed using this bulk metallic glass material at a temperature domain around the β Relaxation. The components of total strain, including ideal elastic strain, anelastic strain, and viscous-plastic strain, were analyzed based on the model of shear transformation zones (STZs). The stochastic activation of STZ contributes to the anelastic strain. When the temperature or external stress is high enough or the timescale is long enough, the interaction between STZs induces viscous-plastic strain. When all the spectrum of STZs is activated, the quasi-steady-state creep is achieved.
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dynamic Mechanical Relaxation behavior of binary metallic glasses
Intermetallics, 2021Co-Authors: M N Liu, Q Hao, J Dong, B A Sun, Shidong Feng, Daniel Crespo, J.c. QiaoAbstract:Abstract Secondary β Relaxation is a fundamental issue to understand the diffusion, plasticity and glass transition behavior of metallic glasses. Binary metallic glasses provide a simple glassy system to probe the dynamic Mechanical processes. In the current research, dynamic Mechanical behavior of the typical binary metallic glasses was investigated by dynamic Mechanical analysis (DMA). The dynamic Mechanical Relaxation behavior of Cu50-xTi50+x (x = 0, 7 and 9) and CuxZr100-x (x = 30, 50, 56, 61.8 and 64) binary metallic glass system was studied. It is found that the β Relaxation becomes pronounced with the increase of copper, which is analyzed in the framework of the principle of mixing enthalpy. However, the β Relaxation of CuZr or CuTi binary metallic glasses is much more modest than that of Y65Co35, Dy65Co35 and Y67Cu33.
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Dynamic Mechanical Relaxation in Bulk Metallic Glasses: A Review
Journal of Materials Science & Technology, 2014Co-Authors: J.c. Qiao, Jean-marc PelletierAbstract:Metallic glasses have aroused considerable interest in the past decades because they exhibit fascinating properties. First, this article briefly outlines the Mechanical, thermal properties and application of the metallic glasses. In addition, we focus on the dynamic Mechanical Relaxation behaviors, i.e. main (α) and secondary (β) Relaxations, in metallic glasses. The Mechanical Relaxation behaviors are connected to the Mechanical properties and physical properties in glassy materials. The main Relaxation in glassy materials is related to the glass transition phenomenon and viscous flow. On the other hand, the β Relaxation is linked to many fundamental issues in metallic glasses. In these materials Relaxation processes are directly related to the plastic deformation mechanism. The Mechanical Relaxations, particularly, the β Relaxation provides an excellent opportunity to design metallic glasses with desired physical and Mechanical properties. We demonstrate the universal characteristics of main Relaxation in metallic glasses. The phenomenological models and the physical theories are introduced to describe the main Relaxation in metallic glasses. In parallel, we show the dependence of the α and β Relaxations on the thermal treatments in metallic glasses. Finally, we analyze the correlation between the atomic mobility and the thermo-Mechanical treatments in metallic glasses. On the one hand, the atomic mobility in metallic glasses is reduced by physical aging or crystallization. On the other hand, the atomic mobility in metallic glass is enhanced by deformation (i.e. compression and cold rolling). Importantly, to analyze the atomic mobility in amorphous materials, a physical theory is introduced. This model invokes the concept of quasi-point defects, which correspond to the density fluctuations in the glassy materials.
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Mechanical Relaxation in a zr based bulk metallic glass analysis based on physical models
Journal of Applied Physics, 2012Co-Authors: J.c. Qiao, J M PelletierAbstract:The Mechanical Relaxation behavior in a Zr55Cu30Ni5Al10 bulk metallic glass is investigated by dynamic Mechanical analysis in both temperature and frequency domains. Master curves can be obtained for the storage modulus G′ and for the loss modulus G′′, confirming the validity of the time-temperature superposition principle. Different models are discussed to describe the main (α) Relaxation, e.g., Debye model, Havriliak-Negami (HN) model, Kohlrausch-Williams-Watt (KWW) model, and quasi-point defects (QPDs) model. The main Relaxation in bulk metallic glass cannot be described using a single Relaxation time. The HN model, the KWW model, and the QPD theory can be used to fit the data of Mechanical spectroscopy experiments. However, unlike the HN model and the KWW model, some physical parameters are introduced in QPD model, i.e., atomic mobility and correlation factor, giving, therefore, a new physical approach to understand the Mechanical Relaxation in bulk metallic glasses.
Andreas Schonhals - One of the best experts on this subject based on the ideXlab platform.
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dielectric and dynamic Mechanical Relaxation behaviour of poly ethylene 2 6 naphthalene dicarboxylate ii semicrystalline oriented films
Polymer, 2003Co-Authors: L Hardy, Isabelle Stevenson, Gisele Boiteux, G Seytre, Andreas Fritz, Andreas SchonhalsAbstract:Abstract The dielectric and dynamic Mechanical behaviour of bi-stretched non-treated and annealed semicrystalline poly(ethylene 2,6-naphthalene dicarboxylate) (PEN) films are studied as a function of different morphologies obtained by thermal treatments at temperatures close to the melting temperature of a semicrystalline film. Differential scanning calorimetry (DSC) shows that the glass transition temperatures do not change significantly with the thermal treatment for bi-stretched films. However, the melting temperatures and the degree of crystallinity increase with the value of annealing temperature. Both dielectric Relaxation spectroscopy (DRS) and dynamic Mechanical analysis (DMA) display three Relaxation processes. In order of decreasing temperature, can be observed: the α-Relaxation due to the glass transition, the β∗-process assigned to cooperative molecular motions of the naphthalene groups which aggregate and the β-Relaxation due to local fluctuations of the carbonyl groups. The α-Relaxation process shifts to higher temperatures for the 250 and 260 °C treated bi-stretched semicrystalline samples compared to the sample thermally treated at 240 °C according to DRS data but shifts to lower temperatures according to the DMA measurements for the three annealed samples. This discrepency results from the different sensitivity of each methods with regards to the release of orientation. At a fixed frequency the temperature associated to β∗-Relaxation is lower for the non-treated bi-stretched semicrystalline samples than for the treated ones using DMA but no difference can be seen in DRS. The associated apparent activation energies are rather high which suggest cooperative motions. It is assumed that the orientation of the samples prevents coupling between the naphthalene groups due to the stretched chain configuration in the amorphous phase. The activation energy for the β-process given by DRS is independent of the thermal treatment and the value agrees with those found for poly(ethylene terephthalate) (PET) and amorphous PEN. Evidence of the decrease of orientation in the sample with thermal treatment can be seen via the onset of mobility, both by DRS and DMA. Thus, the orientation induces a greater change of properties compared to the crystalline samples obtained from the thermal treatment of an amorphous sample. Finally, a three phase model is proposed since there is evidence of a rigid amorphous phase present in PEN biaxially stretched samples which was favoured by the dependence of dielectric Relaxation strengths on the degree of crystallinity for the β∗- and α-Relaxation.
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dielectric and dynamic Mechanical Relaxation behaviour of poly ethylene 2 6 naphthalene dicarboxylate i amorphous films
Polymer, 2001Co-Authors: L Hardy, Isabelle Stevenson, Gisele Boiteux, G Seytre, Andreas SchonhalsAbstract:Abstract The dielectric and dynamic Mechanical behaviour of amorphous poly(ethylene 2,6 naphthalene dicarboxylate) (PEN) and of thermally annealed samples is reported as a function of the morphology. During the treatment at temperatures close to the melting temperatures the samples become semi-crystalline. differential scanning calorimetry (DSC) shows that the glass transition temperatures do not change significantly with the thermal treatment. However the degree of crystallinity as well as the melting temperatures increase with the annealing temperature. Both dielectric (DEA) and dynamic Mechanical (DMA) analysis display three Relaxation processes. In order of decreasing temperature the α-Relaxation due to the glass transition, the β ∗ -process assigned to the out of plane movements of the naphthalene rings or aggregates of it and the β-Relaxation due to local molecular motions of carbonyl groups. The α-Relaxation process shifts to higher temperatures for the semi-crystalline samples compared to the amorphous one. On the contrary, at a fixed frequency the temperature associated to β ∗ -Relaxation is higher for the amorphous sample than for the semi-crystalline ones. The associated apparent activation energies are rather high and depend on the thermal treatment and also surprisingly on the method of measurement. It is concluded that the β ∗ -Relaxation is probably due to cooperative molecular motions of the naphthalene groups which aggregate in the amorphous state and that these aggregates are prevented from forming when the degree of crystallinity changes due to the thermal treatment. Finally, the activation energy for the β-process is nearly independent of the thermal treatment and the value agrees with that found for poly(ethylene terephthalate) (PET).
J M Pelletier - One of the best experts on this subject based on the ideXlab platform.
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dynamic Mechanical Relaxation behavior of zr35hf17 5ti5 5al12 5co7 5ni12cu10 high entropy bulk metallic glass
Journal of Materials Science & Technology, 2021Co-Authors: Liuchao Zhang, Eloi Pineda, J M Pelletier, Daniel Crespo, Y J Duan, Takeshi Wada, Hidemi Kato, J.c. QiaoAbstract:Abstract Non-equiatomic high entropy bulk metallic glasses were reported recently and show unique Mechanical and physical properties. Dynamic Mechanical Relaxation behavior of Zr35Hf17.5Ti5.5Al12.5Co7.5Ni12Cu10 high entropy bulk metallic glass was investigated by dynamic Mechanical analysis (DMA) and the Mechanical spectra could be well described by the quasi-point defects (QPD) theory. Compared to typical metallic glasses, the intensity of the β Relaxation of Zr35Hf17.5Ti5.5Al12.5Co7.5Ni12Cu10 high entropy bulk metallic glass is lower due to the sluggish diffusion. At the same time, the correlation factor χ is higher than that of conventional metallic glasses and this is ascribed to the high configuration entropy. In parallel, physical aging below the glass transition temperature leads to a decrease of atomic mobility, caused by a decrease of the concentration of defects.
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dynamic Mechanical Relaxation and thermal creep of high entropy la30ce30ni10al20co10 bulk metallic glass
Science China-physics Mechanics & Astronomy, 2021Co-Authors: Langting Zhang, Eloi Pineda, J M Pelletier, Daniel Crespo, Y J Duan, Yunjiang Wang, J.c. QiaoAbstract:Dynamic Mechanical Relaxation is a fundamental tool to understand the Mechanical and physical properties of viscoelastic materials like glasses. Mechanical spectroscopy shows that the high-entropy bulk metallic glass (La30Ce30Ni10Al20Co10) exhibits a distinct β-Relaxation feature. In the present research, dynamic Mechanical analysis and thermal creep were performed using this bulk metallic glass material at a temperature domain around the β Relaxation. The components of total strain, including ideal elastic strain, anelastic strain, and viscous-plastic strain, were analyzed based on the model of shear transformation zones (STZs). The stochastic activation of STZ contributes to the anelastic strain. When the temperature or external stress is high enough or the timescale is long enough, the interaction between STZs induces viscous-plastic strain. When all the spectrum of STZs is activated, the quasi-steady-state creep is achieved.
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experimental analysis to the structural Relaxation of ti48zr20v12cu5be15 metallic glass matrix composite
Journal of Alloys and Compounds, 2018Co-Authors: Guojian Lyu, Jichao Qiao, Min Song, J M Pelletier, Yao YaoAbstract:Abstract The Mechanical Relaxation characteristics of in-situ Ti48Zr20V12Cu5Be15 metallic glass matrix composite with dendrites reinforced are investigated by using Mechanical spectroscopy. An abnormal internal friction behavior below the glass transition temperature is detected. Considering the irreversible feature and based on the transmission electron microscopy analysis, the abnormal internal friction behavior is mainly induced by the precipitation of nanocrystals in the dendritic phase. In order to understand better the dynamic Mechanical properties of the Ti48Zr20V12Cu5Be15 metallic glass matrix composite, the kinetic characteristics of glass transition are analyzed in the framework of quasi-point defects theory. In addition, an isothermal annealing conducted at lower than the glass transition temperature induces a significant change on both modulus and loss factor, the kinetics of Relaxation under annealing can be well described by the stretched exponential Relaxation equation.
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understanding of micro alloying on plasticity in cu46zr47 xal7dyx 0 x 8 bulk metallic glasses under compression based on Mechanical Relaxations and theoretical analysis
International Journal of Plasticity, 2016Co-Authors: Jichao Qiao, J M Pelletier, Yao Yao, Leon M KeerAbstract:Abstract Lacking of plasticity at ambient temperature severely hinders the wide applications of bulk metallic glasses, and a significant challenge is to improve the plasticity. Based on the metallurgical physics, micro-alloying can be applied to adjust metallic glasses plasticity. In the current work, dynamic Mechanical Relaxation of Cu 46 Zr 47−x Al 7 Dy x (0 ≤ x ≤ 8) bulk metallic glasses has been investigated experimentally by dynamic Mechanical analysis. Compressive tests have been performed to investigate Mechanical properties of the Cu-based bulk metallic glasses at both ambient as well as cryogenic temperatures. The results indicated that by modifying the chemical composition, plastic deformation and dynamic Mechanical Relaxation processes are changed. The influence of Dysprosium (Dy) on plastic deformation is possibly related to the Johari-Goldstein (JG) Relaxation in the metallic glasses. A kinetic model which may be predict the Mechanical Relaxation behavior and atomic mobility of the metallic glasses. In addition, experimental analyses show that thermal properties can be affected by the Dy addition of the Cu-based bulk metallic glasses. Our investigations demonstrated that micro-alloying of Dy could play an important role to influence the Cu 46 Zr 47−x Al 7 Dy x bulk metallic glasses plasticity. In order to explain this behavior, the quasi-point defects theory was used to describe the microstructural heterogeneity. We postulate that the compressive plasticity is directly associated with local heterogeneity and Relaxation modes for metallic glasses.
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Mechanical Relaxation in a zr based bulk metallic glass analysis based on physical models
Journal of Applied Physics, 2012Co-Authors: J.c. Qiao, J M PelletierAbstract:The Mechanical Relaxation behavior in a Zr55Cu30Ni5Al10 bulk metallic glass is investigated by dynamic Mechanical analysis in both temperature and frequency domains. Master curves can be obtained for the storage modulus G′ and for the loss modulus G′′, confirming the validity of the time-temperature superposition principle. Different models are discussed to describe the main (α) Relaxation, e.g., Debye model, Havriliak-Negami (HN) model, Kohlrausch-Williams-Watt (KWW) model, and quasi-point defects (QPDs) model. The main Relaxation in bulk metallic glass cannot be described using a single Relaxation time. The HN model, the KWW model, and the QPD theory can be used to fit the data of Mechanical spectroscopy experiments. However, unlike the HN model and the KWW model, some physical parameters are introduced in QPD model, i.e., atomic mobility and correlation factor, giving, therefore, a new physical approach to understand the Mechanical Relaxation in bulk metallic glasses.
L Hardy - One of the best experts on this subject based on the ideXlab platform.
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dielectric and dynamic Mechanical Relaxation behaviour of poly ethylene 2 6 naphthalene dicarboxylate ii semicrystalline oriented films
Polymer, 2003Co-Authors: L Hardy, Isabelle Stevenson, Gisele Boiteux, G Seytre, Andreas Fritz, Andreas SchonhalsAbstract:Abstract The dielectric and dynamic Mechanical behaviour of bi-stretched non-treated and annealed semicrystalline poly(ethylene 2,6-naphthalene dicarboxylate) (PEN) films are studied as a function of different morphologies obtained by thermal treatments at temperatures close to the melting temperature of a semicrystalline film. Differential scanning calorimetry (DSC) shows that the glass transition temperatures do not change significantly with the thermal treatment for bi-stretched films. However, the melting temperatures and the degree of crystallinity increase with the value of annealing temperature. Both dielectric Relaxation spectroscopy (DRS) and dynamic Mechanical analysis (DMA) display three Relaxation processes. In order of decreasing temperature, can be observed: the α-Relaxation due to the glass transition, the β∗-process assigned to cooperative molecular motions of the naphthalene groups which aggregate and the β-Relaxation due to local fluctuations of the carbonyl groups. The α-Relaxation process shifts to higher temperatures for the 250 and 260 °C treated bi-stretched semicrystalline samples compared to the sample thermally treated at 240 °C according to DRS data but shifts to lower temperatures according to the DMA measurements for the three annealed samples. This discrepency results from the different sensitivity of each methods with regards to the release of orientation. At a fixed frequency the temperature associated to β∗-Relaxation is lower for the non-treated bi-stretched semicrystalline samples than for the treated ones using DMA but no difference can be seen in DRS. The associated apparent activation energies are rather high which suggest cooperative motions. It is assumed that the orientation of the samples prevents coupling between the naphthalene groups due to the stretched chain configuration in the amorphous phase. The activation energy for the β-process given by DRS is independent of the thermal treatment and the value agrees with those found for poly(ethylene terephthalate) (PET) and amorphous PEN. Evidence of the decrease of orientation in the sample with thermal treatment can be seen via the onset of mobility, both by DRS and DMA. Thus, the orientation induces a greater change of properties compared to the crystalline samples obtained from the thermal treatment of an amorphous sample. Finally, a three phase model is proposed since there is evidence of a rigid amorphous phase present in PEN biaxially stretched samples which was favoured by the dependence of dielectric Relaxation strengths on the degree of crystallinity for the β∗- and α-Relaxation.
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dielectric and dynamic Mechanical Relaxation behaviour of poly ethylene 2 6 naphthalene dicarboxylate i amorphous films
Polymer, 2001Co-Authors: L Hardy, Isabelle Stevenson, Gisele Boiteux, G Seytre, Andreas SchonhalsAbstract:Abstract The dielectric and dynamic Mechanical behaviour of amorphous poly(ethylene 2,6 naphthalene dicarboxylate) (PEN) and of thermally annealed samples is reported as a function of the morphology. During the treatment at temperatures close to the melting temperatures the samples become semi-crystalline. differential scanning calorimetry (DSC) shows that the glass transition temperatures do not change significantly with the thermal treatment. However the degree of crystallinity as well as the melting temperatures increase with the annealing temperature. Both dielectric (DEA) and dynamic Mechanical (DMA) analysis display three Relaxation processes. In order of decreasing temperature the α-Relaxation due to the glass transition, the β ∗ -process assigned to the out of plane movements of the naphthalene rings or aggregates of it and the β-Relaxation due to local molecular motions of carbonyl groups. The α-Relaxation process shifts to higher temperatures for the semi-crystalline samples compared to the amorphous one. On the contrary, at a fixed frequency the temperature associated to β ∗ -Relaxation is higher for the amorphous sample than for the semi-crystalline ones. The associated apparent activation energies are rather high and depend on the thermal treatment and also surprisingly on the method of measurement. It is concluded that the β ∗ -Relaxation is probably due to cooperative molecular motions of the naphthalene groups which aggregate in the amorphous state and that these aggregates are prevented from forming when the degree of crystallinity changes due to the thermal treatment. Finally, the activation energy for the β-process is nearly independent of the thermal treatment and the value agrees with that found for poly(ethylene terephthalate) (PET).
Efthimios Kaxiras - One of the best experts on this subject based on the ideXlab platform.
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modeling Mechanical Relaxation in incommensurate trilayer van der waals heterostructures
Physical Review B, 2020Co-Authors: Ziyan Zhu, Paul Cazeaux, Mitchell Luskin, Efthimios KaxirasAbstract:The incommensurate stacking of multilayered two-dimensional materials is a challenging problem from a theoretical perspective and an intriguing avenue for manipulating their physical properties. Here we present a multiscale model to obtain the Mechanical Relaxation pattern of twisted trilayer van der Waals (vdW) heterostructures with two independent twist angles, a generally incommensurate system without a supercell description. We adopt the configuration space as a natural description of such incommensurate layered materials, based on the local environment of atomic positions, bypassing the need for commensurate approximations. To obtain the Relaxation pattern, we perform energy minimization with respect to the Relaxation displacement vectors. We use a continuum model in combination with the generalized stacking fault energy to describe the interlayer coupling, obtained from first-principles calculations based on density functional theory. We show that the Relaxation patterns of twisted trilayer graphene and ${\mathrm{WSe}}_{2}$ are ``moir\'e of moir\'e,'' as a result of the incommensurate coupling two bilayer moir\'e patterns. We also show that, in contrast to the symmetry-preserving in-plane Relaxation in twisted bilayers, trilayer Relaxation can break the two fold rotational symmetry about the $xy$ plane when the two twist angles are equal.