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1 Introduction
1.1 The Objective of the Work
The subject of the book evolved since the 1990s from the many years' studies, in several joint research projects conducted together with the investigation group of Andrzej Korbel and Włodzimierz Bochniak, professors at the Faculty of Non‐Ferrous Metals of the AGH University of Science and Technology in Kraków, Poland (formerly Akademia Górniczo – Hutnicza, in English: Academy of Mining and Metallurgy), cf. Figure 1.1. It concerned physics and theoretical description of deformation processes in metals, particularly in hard deformable alloys. The long‐time joint efforts to understand the physical mechanisms responsible for observed phenomena coined the subject of this work. Many years of investigations of metal‐forming processes based on multilevel observations – on a macroscopic scale with the naked eye, microscopic ones using optical microscopy, high‐resolution transmission electron microscopy, and scanning electron microscopy – led to the critical conclusion. The traditional approach of classical plasticity theory based solely on crystallographic slip and twinning in separate grains is inadequate for predicting and modelling observed deformation processes. Such an observation played a pivotal role in developing an innovative metal‐forming method called KOBO, the acronym of inventors names ‘Korbel’ and ‘Bochniak’. This book attempts to provide theoretical foundations and empirical evidence of viscoplastic flow produced by shear banding. In the future, the presented results should make the basis for the formulation of computer codes necessary for numerical simulations of deformation processes in industrial applications. It seems that this book might fill at least partly the mentioned gap.
Figure 1.1 The historical AGH UST emblem.
Source: AGH University of Science and Technology (https://www.agh.edu.pl/en/university/history‐and‐traditions/emblem‐and‐symbols/).
1.2 For Whom Is This Work Intended?
The book's readers may be graduate and postgraduate students in engineering, particularly material science and mechanical engineering. Researchers working on the physical foundations of inelastic deformation of metallic solids and numerical simulations of manufacturing processes could also benefit from this study. The content of the work is also directed at specialists in the field of rational mechanics of materials. The prerequisite knowledge of material science and continuum mechanics with related mathematical foundations, as vector and tensor algebra and tensor analysis, will appear helpful for the readers. The fundamental background may provide the recent work written by eminent scholars of great experience, Morton E. Gurtin, Eliot Fried, and Lallit Anand (Gurtin et al. 2009). Also, a modern and integrated study across the different observation scales of the foundation of solid mechanics applied to the mathematical description of material behaviour presented in the pivotal work (Asaro and Lubarda 2006) is recommendable for the readers. These works comprehensively cover the subject of rational thermomechanics, being the contemporary approach of classical treatises ‘standing on the shoulders of giants’ (https://en.wikipedia.org/wiki/Standing_on_the_shoulders_of_giants), cf. Chapter 4 for the discussion of a historical thread.
1.3 State of the Art
1.3.1 Motivation Resulting from Industrial Applications
Korbel and Szyndler (2010) presented an overview of the Polish engineering inventions' contribution to metal‐forming technologies. Three industrial sectors can play an important role: electrical power plants, transportation, and natural environment protection. First of all, one should focus on high‐quality and energy‐saving extrusion and forging processes of the elements made of structural steel, non‐ferrous metals, and light alloys used to produce parts of machines and other equipment manufactured by all industry sectors.
There is a need and necessity to implement innovative technical and technological solutions into metal‐forming practice, making production more efficient, energy‐saving, and less expensive. So, we face three challenges with
