Influence of cooling rate on the structure and properties of a Cu–Zr–Ti–Ag glassy alloy

Louzguine-Luzgin, Dmitri V.; Saito, Tsuneo; Saida, Junji; Inoue, Akihisa

doi:10.1557/jmr.2008.0066

Cited by 24 publications

(11 citation statements)

References 49 publications

(27 reference statements)

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“…The value of the Biot number calculated for typical Cu-and Zr-based glass-forming alloys is about 1 [56] which implies that the temperature gradients inside the melt are non-negligible and both heat transfer through the melt and heat transfer through the melt/mould interface make important contributions to the observed cooling rate in the casting of bulk glassy alloys. [70] The initial thermal gradient depends directly on the metal mould temperature and the liquid metal temperature, and later in the casting process the relative masses of the liquid metal and the mould are also important. It can be argued that the temperature of the liquid metal just prior to casting is not important, since the kinetics of heat transfer only become important once the glass becomes supercooled to temperatures below the equilibrium melting temperature.…”

Section: Extrinsic Parameters Influencing Gfamentioning

confidence: 99%

Intrinsic and Extrinsic Factors Influencing the Glass‐Forming Ability of Alloys

2008

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Bulk glassy alloys (also called bulk metallic glasses, BMGs) currently attract significant attention in the field of materials science. Research on glassy alloys started after the formation of the first Au-Si sample with an amorphous structure in 1960 [1] at a very high cooling rate of 10 6 K/s. The formation of a glassy (amorphous) phase from a melt takes place through the glass-transition phenomenon. [2,3] Metallic glasses are metastable at room temperature and devitrify/crystallize on heating [4,5] above the crystallization temperature T x (b) (b is the heating or cooling rate) for kinetic reasons. [6] A large number of BMGs, defined as 3-dimentional massive glassy articles with a size not less than 1 mm in any dimension, have been produced during the last decade. [7][8][9] BMGs can be obtained at cooling rates of the order of 100, 10, 1 K/s and even less. [10,11] The largest number of metallic glass applications takes advantage of their exceptional and highly tailorable magnetic properties. [12] Bulk glassy alloys exhibit not only high strength, hardness, wear resistance and large elastic deformation, but high corrosion resistance as well. Moreover, the fatigue-endurance limits of Zr-based alloys are comparable with those of high-strength structural alloys. [13] Pt-based [14] and Zr-based [15] bulk metallic glasses were recently reported to exhibit high room-temperature plasticity. Although some explanations have been given, [16,17] the mechanism of plasticity is not fully established.The combination of exceptional structural and functional properties and the ability to produce bulk product forms has led to a significant number of important applications. However, further discovery, development and application of metallic glasses is limited by an understanding of the fundamental features that control glass-forming ability (GFA) and thermal stability. Bulk glassy alloys possess three common features summarized by Inoue, [4,6] i.e., belong to multicomponent systems with 3 or more constituents, have significant mismatch in atomic radii of greater than 12 %, and exhibit large, negative mixing enthalpies (DH) among the constituent elements. A large number of physical-mathematical parameters (determining characteristics) and factors (features contributing to a particular result) have been proposed so far to indicate the GFA of BMGs. These include a number of derived thermal parameters that depend on the glass transition temperature (T g ), the crystallization temperature (T x ) and the liquidus temperature (T l ). [18] Other factors include compositional proximity to a deep eutectic trough [19] and particular distributions in atomic sizes. [20]. However, none of these guidelines have been established to be sufficiently robust and predictive to be considered as necessary and sufficient for bulk glass formation.In the present paper we consider solidification of a metallic liquid phase by casting and will discuss kinetic, [21,22] thermodynamic, processing and other factors [23,24] as well as semi-empirical parameters ...

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Section: Extrinsic Parameters Influencing Gfamentioning

confidence: 99%

Intrinsic and Extrinsic Factors Influencing the Glass‐Forming Ability of Alloys

2008

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“…The microstructure of these two metallic glass phases provides an opportunity for developing new materials with unique properties. Even though metallic glass material has been comprehensively studied, the development of this material is blocked by the expensiveness, limit, and cooling rate of its complex synthesis with high expense [15,16], thus restricting the application in engineering. In recent years, the appearance of thin film metallic glasses (TFMGs) has drawn increasing attention, and some systems with various compositions showing great glass-forming ability (GFA) and superior properties have been comprehensively studied [17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Fabrication, Corrosion, and Mechanical Properties of Magnetron Sputtered Cu–Zr–Al Metallic Glass Thin Film

Wei

Ying

et al. 2019

Materials

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The appearance of thin film metallic glasses (TFMGs) is gaining increasing interest because of their unique mechanical and anticorrosion properties and potential engineering applications. In this study, Cu-Zr-Al ternary thin film metallic glasses were fabricated by using DC magnetron sputtering equipment with various target powers. The evolution of the structure was systematically investigated by grazing incidence X-ray diffractometer, scanning electron microscopy, and transmission electron microscopy. The deposition rate increases with the increasing of applied target power. The as-deposited thin films show an amorphous structure. The compositional fluctuations on the nanometer scale indicate the presence of two Cu-and Zr-rich amorphous phases. The electrochemical corrosion measurements indicated that Cu-Zr-Al thin film metallic glasses had good corrosion resistance in the sulfuric acid solution. Nanoindentation results showed that the mechanical deformation was found to be homogenous and reproducible with a high value range for the hardness and modulus.

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“…Lacking long-range periodicity, MGs can be considered as solids with frozen-in liquid structures, which are composed of tightly bonded atomic clusters and free-volume zones [6]. Being in a metastable state, the glassy structure of MGs is most likely to be affected by different variables arising in the stage of materials preparation, for example, cooling rate, overheat temperature, and impurities [7][8][9], among which the cooling rate was thought to play an important role in the vitrification of MGs [10][11][12]. In that case, it was argued that the mechanical properties of MGs could also be affected by the cooling rate [11,13].…”

Section: Introductionmentioning

confidence: 99%

“…Being in a metastable state, the glassy structure of MGs is most likely to be affected by different variables arising in the stage of materials preparation, for example, cooling rate, overheat temperature, and impurities [7][8][9], among which the cooling rate was thought to play an important role in the vitrification of MGs [10][11][12]. In that case, it was argued that the mechanical properties of MGs could also be affected by the cooling rate [11,13]. The increase of the cooling rate may result in configurationally looser atomic packing and thus, more free-volume zones [14,15], which therefore contributes to larger plasticity [16][17][18].…”

Section: Introductionmentioning

confidence: 99%