Abstract
Optimal estimation of the diffraction observations over the object reliably detects periodicity in the dislocation structure of martensitic transformation as an exhibition of its wave nature. The period along normal to the slip planes is comparable with the radius of dislocation loops in crystals. The measured degree of one-dimensional long-range order in the arrangement of the loops is close to the upper limit equal to unity. Subject to the theory of metals, the observed structure could be generated by quantum lattice vibrations, which actuate a jump-like phase transition. A simple explanation exists: after a sharp fall in temperature, the excess energy of conduction electrons causes the crystal to expand instantly with the transformation of translational symmetry. Internal shifts of the crystal lattice caused by electron-phonon interactions concurrently trigger the wave process of formation of thin martensitic plates in the surrounding matrix, which are observed in metallography. Based on an in-depth analysis of the dislocation structure of martensite crystals, a physically founded concept is advanced in which the martensitic transformation is a macroscopic quantum phenomenon connected with the symmetry properties of a crystal system in metals.
Highlights
With the discovering of a strong long-range order in the system of dislocation loops, it becomes cleared that microscopic shifts are generated by relaxation vibrations of the crystal lattice at the moment of equilibrium disturbance
Information is available on the one-dimensional long-range order in the system of small dislocation loops, which is existed in the lower harmonics of diffraction line with large reflection indices {HKL}
The periodic dislocation structure revealed itself, giving rise to an image of a hardened wave of lattice vibrations. It is known the process of emission of long-wavelength phonons by “hot” electrons in low-temperature relaxation of the system. [8]
Summary
The diffraction theory of dislocation systems in the crystals is applicable to the entire space of structures: disorder (chaotic network), short-range order (random clusters) and long-range order (regular placement) [1]. The main propositions of the theory that is basis of the method for studying the dislocation structure of highly distorted crystals are specified in [2]. Analysis of the dislocations system arising in crystals upon martensitic transformation reveals one's nature. A high concentration of fine dislocation loops indicates that phase transformation the microscopic shifts carry out, together transforming the symmetry of crystals [2]. With the discovering of a strong long-range order in the system of dislocation loops, it becomes cleared that microscopic shifts are generated by relaxation vibrations of the crystal lattice at the moment of equilibrium disturbance. Measuring the order parameters in the dislocation structure of crystals by method created is presented using the example of carbon steel tetragonal martensite
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