Phase separation and improved plasticity by modulated heterogeneity in Cu–(Zr,Hf)–(Gd,Y)–Al metallic glasses

Park, Eun Soo; Kyeong, Joon Seok; Kim, D.H.

doi:10.1016/j.scriptamat.2007.03.008

Cited by 109 publications

(62 citation statements)

References 20 publications

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“…In 2004, Kündig et al reported two-phase glassy alloys in the Zr-La-Al-Ni-Cu system [6]. In the following years, phase separated metallic glasses were successfully prepared in several alloy systems: Zr-Y-Co-Al [7], Ni-Nb-Y [8], ZrNd-Al-Co [9], Cu-(Zr,Hf)-(Gd,Y)-Al [10], and Zr-(Ce,Pr,Nd)-Al-Ni [11]. In all these cases, phase separation leads to a special microstructure with a length-scale up to several micron and some self similar features are observed by transmission electron microscopy (TEM) [6,12,13].…”

Section: Introductionmentioning

confidence: 99%

Spinodal decomposition of Ni–Nb–Y metallic glasses

et al. 2009

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Section: Introductionmentioning

confidence: 99%

Spinodal decomposition of Ni–Nb–Y metallic glasses

et al. 2009

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“…the liquid drops become amorphous or crystalline. In recent years such novel amorphous/amorphous [10][11][12][13] or amorphous / crystalline [14-16] composites have been synthesized.…”

Section: Introductionmentioning

confidence: 99%

“…the liquid drops become amorphous or crystalline. In recent years such novel amorphous/amorphous [10][11][12][13] or amorphous / crystalline [14-16] composites have been synthesized.Our subject is the study of the liquid immiscibility in the Ag-Cu-Zr system, in which the homogenous liquid separates into an Ag-rich liquid (L 1 ) and into a Cu-Zr-rich liquid (L 2 ) during cooling through the miscibility gap [17][18]. In the present work nickel (Ni) and yttrium (Y) are separately added to the Ag-Cu-Zr system and their influence is studied on liquid immiscibility.…”

mentioning

confidence: 99%

Effect of Y and Ni addition on liquid immiscibility in Cu–Zr–Ag ternary alloys

Janovszky

Tomolya

Svéda

et al. 2014

Journal of Alloys and Compounds

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Liquid immiscibility was studied in Cu-Zr-Ag-Y and Cu-Zr-Ag-Ni liquid alloy systems. In case of Y addition the liquid decomposes into an Ag-Y rich liquid (L 1 ) and into a Cu-Zr rich liquid (L 2 ). In case of Ni addition the separated liquid phases are Ag-rich and Cu-Zr-Ni rich liquids. Different microstructures were found as function of the volume fraction of the L 1 liquid phase. The Y addition increased the field of miscibility gap of the ternary Cu-Zr-Ag system to a greater extent compared to Ni addition. Also, the rate of coalescence of droplets in the Cu-Zr-Ag-Y system was considerably larger compared to the Cu-Zr-Ag-Ni system. These two observations are interconnected: increased miscibility means more positive excess Gibbs energy, which leads to higher liquid/liquid interfacial energy, being the driving force of coalescence. Alloys with different compositions taken from the tip of the wedge have been studied by DSC. The amorphous fraction progressively reduces when increasing the Ag-content. A small amount of amorphous phase was detected by DSC in the alloy with Ag contents of not greater than 50 at%.Keywords: Ag-Cu-Zr alloy, Liquid-liquid separation, Miscibility gap, Monotectic, Rapid solidification IntroductionCopper-zirconium (Cu-Zr) bulk metallic glasses (BMGs) have been developed due to their lower cost compared to Zr-based BMGs [1-6]. As the BMGs are quite brittle, their further development was necessary to improve their ductility, which can be achieved in three ways: either by extrinsically adding a second crystalline phase to the amorphous matrix [7] or by intrinsic phase separation [8] or by partial nanocrystallization of the amorphous matrix [9]. It is worth noting that the second phase`s shape and morphology are also very important parameters affecting mechanical properties. The second phase with sharp edges is a stress concentration site, so it reduces toughness. In contrast a spherical second phase improves the mechanical properties. The liquid phase separation meets these requirements: i. the separated phase forms spherical, generally liquid drops; ii. the liquid drops become amorphous or crystalline. In recent years such novel amorphous/amorphous [10][11][12][13] or amorphous / crystalline [14-16] composites have been synthesized.Our subject is the study of the liquid immiscibility in the Ag-Cu-Zr system, in which the homogenous liquid separates into an Ag-rich liquid (L 1 ) and into a Cu-Zr-rich liquid (L 2 ) during cooling through the miscibility gap [17][18]. In the present work nickel (Ni) and yttrium (Y) are separately added to the Ag-Cu-Zr system and their influence is studied on liquid immiscibility. These two alloying elements have been chosen to check the effect of the heat of mixing between silver (Ag) and the given element: the heat of mixing in the Ag-Y system is highly negative [19]) while that in the Ag-Ni system is positive [20].

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“…In bulk metallic glass forming alloys the addition of elements with strong positive enthalpy leads to improvement of ductility [4] or glass forming ability [5] in a certain composition range. Phase separated metallic glasses have been prepared in several alloy systems by rapid quenching the melt : Zr-Y-Al-Ni [6], Zr-La-Al-Ni-Cu [7], Zr-Y-Co-Al [8], Ni-Nb-Y [9], Zr-Nd-Al-Co [10] , Cu-(Zr,Hf)-(Gd,Y)-Al [11], and Zr-(Ce,Pr,Nd)-Al-Ni [12]. The phase separation of the liquid is determined by the thermodynamic properties of the alloy system.…”

Section: Introductionmentioning

confidence: 99%

“…The phase separation of the liquid is determined by the thermodynamic properties of the alloy system. For the phase separated metallic glasses reported in [6][7][8][9][10][11][12] the critical temperature of liquid-liquid phase separation T c is above the liquidus temperature. In this case, phase separation leads to a special microstructure with a length scale up to several microns and some self-similar features are observed by transmission electron microscopy [6,13,14].…”

Section: Introductionmentioning

confidence: 99%

Phase separation in Ni70Nb30−Y glasses

Mattern¹,

Vainio²,

Schwarz³

et al. 2010

Intermetallics

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Phase separated metallic glasses were prepared in the ternary Ni-Nb-Y system by rapid quenching of the melt. For Ni-rich alloys, early stage of spinodal decomposition or an almost homogeneous glassy state is obtained due to the reduction of the critical temperature of liquid-liquid phase separation near to the glass transition temperature. In situ small-angle X-ray scattering at elevated temperature gives evidence of on-going phase separation of the glass prior to crystallisation. The structural changes during isothermal heat treatment point to a spinodal mechanism of the decomposition. For glass with low Y-content (5 at %) no indication of phase separation is found in accordance with the composition dependence of the metastable miscibility gap of the supercooled liquid. Upon heating, the phase separated glass becomes a precursor and causes the nanostructure of the Ni2Y-phase formed as the first stage of crystallization. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64

show abstract

Phase separation and improved plasticity by modulated heterogeneity in Cu–(Zr,Hf)–(Gd,Y)–Al metallic glasses

Cited by 109 publications

References 20 publications

Spinodal decomposition of Ni–Nb–Y metallic glasses

Spinodal decomposition of Ni–Nb–Y metallic glasses

Effect of Y and Ni addition on liquid immiscibility in Cu–Zr–Ag ternary alloys

Phase separation in Ni70Nb30−Y glasses

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