Amorphous and Nanocrystalline Metallic Alloys

In this chapter, evolution of structure and properties of amorphous alloys is discussed. Amorphous structure change before crystallization is analyzed for a lot of systems. Structure and property changes are discussed for both amorphous and amorphous‐nanocrystalline materials. Nanocrystal formation in metallic glasses is considered at heating and deformation

The Effect of Free Volume on the Crystallization of Al87Ni8Gd5 Amorphous Alloy

The effect of free volume on the process of crystallization of an Al87Ni8Gd5 amorphous alloy is investigated. The deformation of the amorphous alloys leads to the formation of shear bands, which contain an enhanced free volume concentration. To retain the free volume the amorphous alloy was coated with a layer of a refractory metal. The structure of the Al87Ni8Gd5 alloy with a protective Ta coating was studied by X-ray diffraction and transmission electron microscopy methods. The fraction of the nanocrystalline phase formed in the amorphous samples with a protective Ta coating under annealing was found to be larger than that in the uncoated samples. The size of Al nanocrystals formed in the coated and uncoated samples is the same. A higher rate of crystal nucleation in the deformed amorphous samples with a protective coating is caused by a higher diffusion coefficient due to an enhanced free volume concentration

Specific Features of Structure Transformation and Properties of Amorphous-Nanocrystalline Alloys

This work is devoted to a brief overview of the structure and properties of amorphous-nanocrystalline metallic alloys. It presents the current state of studies of the structure evolution of amorphous alloys and the formation of nanoglasses and nanocrystals in metallic glasses. Structural changes occurring during heating and deformation are considered. The transformation of a homogeneous amorphous phase into a heterogeneous phase, the dependence of the scale of inhomogeneities on the component composition, and the conditions of external influences are considered. The crystallization processes of the amorphous phase, such as the homogeneous and heterogeneous nucleation of crystals, are considered. Particular attention is paid to a volume mismatch compensation on the crystallization processes. The effect of changes in the amorphous structure on the forming crystalline structure is shown. The mechanical properties in the structure in and around shear bands are discussed. The possibility of controlling the structure of fully or partially crystallized samples is analyzed for creating new materials with the required physical properties

Development of Students' Speech Communication on the Basis of a Conscious Attitude to the Study of a Foreign Language

One of the priorities of educational policy today is to improve the quality of the vocational education system associated with the training of competent and competitive specialists. This task has to be carried out in the course of systematic activity of university teachers since the discipline “Foreign language” is usually focused on the formation of a specialist who will have to work in a multicultural environment. In this regard, higher education needs effective teaching technologies that contribute to the process of intensifying university education, which is due to the integration of professional, linguistic and general cultural training of specialists. At the same time, the development of foreign language verbal communication should be a complex educational process, which, in addition to teaching students a foreign language, should also presuppose the formation of a high culture of interpersonal communication. The article investigated the following problems of the development of students' speech communication on the basis of a conscious attitude to the study of a foreign language: Components of foreign language speech communication; Functions of speech communication for the purposes of communication; Semiotic, Imitation and Social teaching models that are included in the content and forms of development of foreign language speech communication; Pedagogical potential of students' speech communication based on a conscious attitude to the study of a foreign language; Indicators of the emerging foreign language competence; Indicators of a conscious attitude towards learning a foreign language in the framework of the development of speech communication

Development of Students' Speech Communication on the Basis of a Conscious Attitude to the Study of a Foreign Language

One of the priorities of educational policy today is to improve the quality of the vocational education system associated with the training of competent and competitive specialists. This task has to be carried out in the course of systematic activity of university teachers since the discipline “Foreign language” is usually focused on the formation of a specialist who will have to work in a multicultural environment. In this regard, higher education needs effective teaching technologies that contribute to the process of intensifying university education, which is due to the integration of professional, linguistic and general cultural training of specialists. At the same time, the development of foreign language verbal communication should be a complex educational process, which, in addition to teaching students a foreign language, should also presuppose the formation of a high culture of interpersonal communication. The article investigated the following problems of the development of students' speech communication on the basis of a conscious attitude to the study of a foreign language: Components of foreign language speech communication; Functions of speech communication for the purposes of communication; Semiotic, Imitation and Social teaching models that are included in the content and forms of development of foreign language speech communication; Pedagogical potential of students' speech communication based on a conscious attitude to the study of a foreign language; Indicators of the emerging foreign language competence; Indicators of a conscious attitude towards learning a foreign language in the framework of the development of speech communication

Changes in the Structure of Amorphous Alloys under Deformation by High-Pressure Torsion and Multiple Rolling

X-ray diffraction and scanning electron microscopy were used to study changes in the structure of amorphous alloys under deformation by high-pressure torsion and multiple rolling. The change in mean nearest neighbor distance (the radius of the first coordination sphere) under deformation was determined. During deformation, shear bands are formed in amorphous alloys, which are regions of lower density compared to the surrounding undeformed amorphous matrix. Shear bands are zones of increased free volume, in which crystallization processes are facilitated. The change in the proportion of free volume under deformation of various types was estimated. The formation of shear bands leads to the appearance of steps on the surface of the samples. The number of shear bands and the surface morphology of deformed amorphous alloys were determined by the type of deformation and the physical properties of the material. The results obtained are discussed within the concept of free volume in the amorphous phase

Changes in the Structure of Amorphous Alloys under Deformation by High-Pressure Torsion and Multiple Rolling

X-ray diffraction and scanning electron microscopy were used to study changes in the structure of amorphous alloys under deformation by high-pressure torsion and multiple rolling. The change in mean nearest neighbor distance (the radius of the first coordination sphere) under deformation was determined. During deformation, shear bands are formed in amorphous alloys, which are regions of lower density compared to the surrounding undeformed amorphous matrix. Shear bands are zones of increased free volume, in which crystallization processes are facilitated. The change in the proportion of free volume under deformation of various types was estimated. The formation of shear bands leads to the appearance of steps on the surface of the samples. The number of shear bands and the surface morphology of deformed amorphous alloys were determined by the type of deformation and the physical properties of the material. The results obtained are discussed within the concept of free volume in the amorphous phase

The Influence of Internal Stress on the Nanocrystal Formation of Amorphous Fe73.8Si13B9.1Cu1Nb3.1 Microwires and Ribbons

The early stages of nanocrystallization in amorphous Fe73.8Si13B9.1Cu1Nb3.1 ribbons and microwires were compared in terms of their internal stress effects. The microstructure was investigated by the X-ray diffraction method. Classical expressions of crystal nucleation and growth were modified for microwires while accounting for the internal stress distribution, in order to justify the XRD data. It was assumed that, due to the strong compressive stresses on the surface part and tensile stresses on the central part, crystallization on the surface part of the microwire proceeded faster than in the central part. The results revealed more rapid nanocrystallization in microwires compared to that in ribbons. During the initial period of annealing, the compressive surface stress of a microwire caused the formation of a predominantly crystallized surface layer. The results obtained open up new possibilities for varying the high-frequency properties of microwires and their application in modern sensorics