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Despite a huge expansion of research on compositionally complex alloys, CCA (such as the entropy alloys, HEA and the corresponding glassy alloys) their comprehension is still limited, which is detrimental both for the design of CCAs and for their application. The broad compositional range in CCAs enables simple tuning of their properties by varying the contents of their constituent elements. Accordingly, the study of transition from CCA to conventional alloy, CA composed from the same constituents is important, both for understanding the formation of solid solutions in CCAs and for proper evaluation of their potential with respect to that of CAs. However, this transition has so far been studied systematically in only two types of alloys: isopleths of the Cantor alloy and glassy TiZrNbCuNi/Co alloys with variable Co, Ni or Cu content (Materials 14 (2021) 5824 and ref. therein). In both alloy systems the variation of a given property with composition depends sharply on the selected principal component and can be either monotonic (like that in the ideal solid solution) or non-monotonic. When the variation is non- monotonic, the maximum value of the selected property is usually outside of HEA composition range.

Despite a huge expansion of research on compositionally complex alloys, CCA (such as the approximately equimolar, multi-component high- entropy alloys, HEA and the corresponding high- entropy glassy alloys), their basic understanding is still limited, which is detrimental both for the design of CCAs and for their application. In particular, the prediction of compositions capable of forming random solid solutions (RSSs) and the prediction of their properties is still a problem. Nevertheless, some properties of a few CCAs exceed those of conventional alloys (CA) [1].

U ovom radu su termodinamički istražena dva sustava metalnih stakala, binarni NiZr i ternarni CuHfTi. Binarnom Ni_23Zr_77 prethodno proizvedenom na Prirodno-matematičkom fakultetu Univerziteta u Sarajevu, provjerena je homogenost, kemijski sastav, struktura, termička stabilnost i mikrotvrdoća. Sustav Cu_55Hf_45-xTi_x (x=0, 5, ..., 45) je već bio prethodno karakteriziran na ovaj način. Na uzorcima oba sustava je izmjeren toplinski kapacitet (C_p) od 2 K do sobne temperature. Iz mjerenja toplinskog kapaciteta su određeni odgovarajući niskotemperaturni termodinamički parametri i ispitana je njihova korelacija sa sposobnošću stakljenja metalnih stakala (GFA - Glass Forming Ability). Bozonski vršak (BP - Boson Peak), koji se inače definira kao višak vibracijskih stanja na niskim frekvencijama u odnosu na fononski spektar kristala i kod mjerenja C_p-a se registrira kao široko ispupčenje u ovisnosti C_p/T^3 vs. T na temperaturama oko 10 K, kod uzorka Ni_23Zr_77 nije detektiran. Zagrijavanjem uzorka različitim brzinama određivana su staklišta iz kojih je određen njegov indeks fragilnosti. Dobijeni rezultati su neuobičajeni i znatno se razlikuju od očekivanih, zašto je u radu ponuđeno i odgovarajuće mikroskopsko objašnjenje. Za sustav CuHfTi je uočeno skaliranje amplitude BP-a s Debyevim doprinosom, dok su niskotemperaturni parametri C_p-a i intenzitet BP-a pokazali linearnu ovisnost s udjelom titana, bez korelacije s GFA. In this thesis we investigated two systems of metallic glasses, binary NiZr and ternary CuHfTi. The binary NiZr system had been produced at the Faculty of Science in Sarajevo and it was investigated for its homogeneity, chemical composition, structure, thermal stability and microhardness, while Cu_55Hf_45-xTi_x (x=0, 5, ..., 45) system had already been examined by the same methods. Samples of both systems were examined by measurement of the heat capacity (C_p) in temperature range from 2 K to room temperature. Low temperature C_p parameters were determined and their relationship with glass forming ability (GFA) was checked. C_p of amorphous materials at sufficiently low temperature deviates from the Debye T^3 law with two major anomalies: almost linear contribution to the C_p below 1 K and a wide peak approximately at 10 K called boson peak (BP). Boson peak (BP) can be defined as an excess of low energy vibrational density of states compared to phonon contribution. A BP has been attributed to the localized vibrations, vibrations of medium range structures, localized defects, hybridization with localized vibrations. . . . On the other hand, BP has been attributed to Van Hove singularities in low-lying transverse acoustic phonon branch which produce similar excess contribution in crystalline materials. A BP was not observed in Ni_23Zr_77. The sample Ni_23Zr_77 was heated at different heating rates in order to detect the glass transition temperature and determine the fragility parameter. The obtained results are unusual, but we offer an appropriate microscopic explanation. The free volume can be reduced and therefore eliminate BP what can be achieved by slow cooling during the production process. In Ni_23Zr_77 the estimated cooling rate (h) is quite high, barely lower than typical h for melt spinning. We can tentatively suggest that the cooling rate close to h_c ~10^4 K/s is responsible for lack of BP. The results of our analysis show that in CuHfTi metallic glasses C_p parameters, position and amplitude of the BP exhibit monotonous dependence on the Ti content while the amplitude of BP scales with the amplitude of Debye contribution what may indicate that BP in this system is related to Van Hove singularity equivalent in glasses. Finally, it may be concluded that BP in metallic glasses of early and late transition metals does not reflect the glass forming ability of the alloys.

We have studied low temperature specific heat (LTSH) in different glass-forming metallic alloys: binary marginal glasses ZrNi [1], bulk metallic glasses CuHfTi [2] and high entropy metallic glasses TiZrNbCuNi(Co) [3]. The results concerning so-called boson peak (BP) contribution to the density of vibrational states in excess to the Debye contribution are quite varied between these alloys. While Zr77Ni23 does not show BP, in Cu55Hf45- xTix its position and amplitude vary monotonously with the Ti content, Fig. 1. In TiZrNbCuNi(Co) alloys with multiple principle elements, the position of BP scales roughly with the Debye temperature, while its amplitude shows more complex behaviour. We discuss these results in respect of the intrinsic differences between these alloys [4] and in the view of different theories of BP, see e.g. [5, 6]. [1] A. Salčinović Fetić et al., Phys. Rev. B 96 (2017) 064201. [2] G. Remenyi et al., Appl. Phys. Lett. 104 (2014) 171906. [3] E. Babić et al., J. Mater. Res. 33 (2018) 3170. [4] W. H. wang, JOM 66 (2014) 2076. [5] T. Brink et al., Phys. Rev. B 94 (2016) 224203. [6] M. Baggioli and A. Zaccone, Phys. Rev. B 122 (2019) 145501.

TEM Journal; Vol 5, No 3, 2016. ISSN 2217-8309, This paper presents the results of an extensive research of partially crystalline Zr77Ni23 metallic glass (indicated numbers refer to atomic percentages). The partially crystalline Zr77Ni23 samples were prepared by melt-spinning using a device constructed in the Metal Physics Laboratory, Faculty of Science in Sarajevo. XRD pattern shows crystalline peaks which correspond to an orthorhombic structure of Zr3Ni superimposed on an amorphous pattern. Homogeneity and chemical composition were investigated using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Crystallization was studied by differential scanning calorimetry (DSC). DSC analysis indicated a simple thermally activated process. Overall activation energy of the crystallization was calculated using Kissinger's model for nonisothermal process and compared with those given by the Augis-Bennett model. By monitoring of the electrical resistance in the temperature range 80 – 270 K a small and negative thermal coefficient of electrical resistance was observed. This means that electrical resistance varies slightly with temperature and it makes this metallic glass suitable for application in electronic circuits for which this property is an important requirement.

We have investigated correlation between thermodynamic parameters given by low- temperature heat capacity (Cp) measurements and glass forming ability (GFA) of NiZr and CuHfTi metallic glasses. Cp of metallic glasses at sufficiently low temperature deviates from the Debye T3 law with a very well known anomaly named Boson peak (BP) which can be observed as a wide peak in Cp/T3(K) approximately at 10 K. Cp measurements were conducted in wide temperature range from 1.8 K to 300 K for as cast and relaxed Ni23Zr77 and Cu55Hf45-xTix (x=0, 5, ... and 45) samples. BP, given as subtraction of the measured Cp and sum of the Debye phonon and electronic contributions, surprisingly in NiZr sample having a low GFA was not detected [1]. Low temperature phonon and electronic contributions to Cp of CuHfTi system depend monotonically on Ti concentration (x), same as reported before [2], but BP has pronounced maximum for Ti concentrations with enhanced GFA. Finally, we can conclude that GFA can be related with low temperature properties of alloys and the strength of BP could be a measure of GFA for metallic glasses produced under the same conditions [3]. [1] A. Salčinović Fetić et al., Phys. Rev. B 96, 064201 (2017) [2] G.Remenyi, et al., Appl. Phys. Lett. 104, 171906 (2014) [3] D. Starešinić, A. Salčinović Fetić, G. Remenyi, I. A. Figueroa, E. Babić, K. Biljaković, Can intensity of BP be a measure of GFA?, under preparation

The formation of transition metal compounds (TC) in selected devitrified high-entropy (HE) and conventional metallic glasses (MG) has been studied by using X-ray diffraction (XRD) and magnetic susceptibility (χ) measurements. The alloys selected were Al0.5TiZrPdCuNi [1], (TiZrNbL)1-xMx (L = Cu, Ni ; M = Fe, Co, Ni, Cu) [2] HEMGs, as well as conventional binary and ternary MGs containing early (TE) and late (TL) transition metals, such as the Ti, Zr, Hf – L [3] and Zr-Cu-Al alloys. Such study provides a comparison between the crystallization patterns in TE-TL HEMGs and these in conventional MGs with the same constituents, which can help to understand the differences in glass forming ability (GFA) between HEMGs and conventional MGs [2, 3]. The measurements of χ on both as-cast and crystallized alloys provide an insight into the changes of electronic structure (ES) accompanying transition from amorphous to crystalline (TCs) state, which seem to determine GFA of TE-TL alloys [3]. Further, the values of χ for crystallized alloys, χc, enable in principle the determination of χc values corresponding to particular TCs. These χc (TC) values in addition to giving an insight into contribution of given TC to ES also enable the determination of the fractions of TCs in a given alloy. This is important for a quantitative analysis of the phase contents in alloys in which the crystalline texture make the determination of phase contents from XRD less accurate. Wherever possible we compare and combine our data with the results from literature. _____________________________________________ ∗ This work was supported by UNAM-DGAPA-PAPIIT project No. IN101016 and Osijek University project IZIP2016-3. † [1] A. Takeuchi et al, Mater. Trans. 54 (2013) 776 ; [2] K. Biljaković et al., J. Alloys Compd. 695 (2017) 2661 and I. A. Figueroa et al., submitted to J. Alloys Compd. ; [3] R. Ristić et al., EPL 114 (2016) 17006 and E. Babić et al., submitted to Phil. Mag..

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Pulsed laser deposition (PLD) has become the most important technique for the production of new materials with complex stoichiometry and multilayered structures. In this paper we present parameters that influence the production of K0.3MoO3 (KBB) thin films by PLD. KBB is a quasi-one-dimensional (q-1D) conductor that exhibits transition to a new ground state of charge density wave (CDW) below a transition temperature Tp. It is considered to be a “canonical“ CDW system and its properties have been extensively researched in bulk. In recent years, production of KBB thin films has enabled investigation of CDW properties in the conditions of reduced dimensionality. Choice of deposition parameters highly influences production of the films and therefore it is essential to investigate it in order to obtain high quality films. This investigation enables one to determine optimal conditions for the production of KBB thin films by PLD.

In the last decade, we have produced several series of thin films of charge density wave (CDW) system K0.3MoO3 by pulsed laser deposition [1-4]. Films have granular structure with typically sub- micron grain size, resulting in somewhat suppressed CDW transition and electric conductivity governed by the variable range hopping mechanism. Recently, for the first time, we have obtained an order of magnitude longer (2-4 m) and well patterned grains, as shown by AFM images in the Figure 1. Electrical conductivity and femtosecond pump- probe response in these films exhibit significant similarity with bulk samples, while the grain length is comparable to the CDW coherence length.

We present an experimental investigation of the fragility and heat capacity of metallic glass Zr77Ni23. The ribbon sample was produced by melt-spinning technique. Glass transition temperature Tg obtained by differential scanning calorimetry with various heating rates was used to estimate fragility parameter m. Heat capacity measurements were performed in a wide temperature interval, ranging from 1.8 K up to room temperature, for as-cast and relaxed samples in different magnetic field strengths. Our results do not show any excess of ibrational density of states over the Debye contribution corresponding to the boson peak. Relaxation of the sample causes a slight decrease of Debye contribution consistent with the measured increase of Young modulus. The fact that no boson peak is observed in heat capacity, together with the obtained intermediate fragility of m=53, positions Zr77Ni23 well outside established correlations between fragility, boson peak strength, and glass forming ability.

Unlike many metallic glasses, CuHfTi system for some concentrations can form bulk metallic glass. In order to establish possible correlation between glass forming ability (GFA) and thermodynamic parameters we have measured heat capacity (Cp) for Cu55Hf45-xTix (x=0, 5, 10, ..., 45) system ranging from 1.8 K up to room temperature for as-cast and annealed samples. Cp of metallic glasses in general does not obey known phonon T3 law which predicts Debye model and one of the anomalies is a wide peak around 10 K which is known as boson peak (BP). Here, we present low-temperature Cp parameters and the intensity of the BP given as subtraction of the measured heat capacity and sum of the Debye phonon and electronic contribution as a function of x. The intensity of BP correlates well with GFA of studied CuHfTi alloys.

Partially crystalline metallic glasses Zr53Cu40Al7, Zr43, 5Cu47, 5Al9 and Zr40Cu53Al7 in the form of ribbons were obtained by melt- spinning. The diffractogram (XRD) confirmed the existence of crystalline peaks superimposed on an amorphous matrix. Scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy was performed to examine the homogeneity and chemical composition of the material. The crystallization process was observed using differential scanning calorimetry (DSC). The electrical resistivity of partially crystalline ZrCuAl metallic glasses has been studied as a function of temperature between 80 and 273 K. The temperature dependence of the resistivity was monitored by standard four-point probe method for compositions with less than 10% Al. Despite the fact that the samples were partially crystalline, a low negative temperature coefficient of resistivity (TCR) similar to that of an amorphous metallic glass is observed.

Metallic glasses are metastable amorphous structures produced by quenching-rapid cooling. Due to very high cooling rates during the production process it is very difficult to produce homogenous samples with the same chemical composition. We present the results of examination of homogeneity and structure of CuZrAlY metallic glass ribbons. The ribbons, approximately 1.5 m long and 1 mm wide were produced using melt spinning technique. The investigated samples, 1 cm long and 1 mm wide were chosen from the middle and the end of produced ribbons. The surface of the samples was examined by metallographic and electron scanning microscopy. Chemical composition in different areas of each sample was checked by energy-dispersive X-ray spectroscopy. The differences in structure of the samples were investigated using X-ray diffraction. Electrical resistivity measurement in temperature range from 80 to 300 K are presented also.

This paper presents the results of an extensive research of two partially crystalline samples Ni23Zr73 (indicated numbers refer to atomic percentages) metallic glasses produced by chill block melt-spinning (CBMS) under different conditions. Keeping all other CBMS parameters constant we have varied only pressure which ejects a stream of liquid onto the wheel. Partially crystalline structure of the samples was confirmed by X-ray characterization (XRD). The samples were also investigated by scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDX). The results showed the very homogenous distribution of nickel and zirconium in the samples and chemical composition near Ni23Zr77. Crystallization and thermal stability were studied by meaning of differential scanning calorimetry (DSC). DSC analysis indicates a simple thermally activated process for both samples. Microhardness was also measured on both sides the samples.