Sukhomlin G. Structure and Properties of Large-Angle Special Crystal and Phase Boundaries in the Commercially Produced Metals and Alloys.

The thesis makes a further progress in the conception of structure and property formation in low-energy special boundaries by the concept of coincidence site lattices (CSL). Crystallographic properties of crystal and phase boundaries and their derivatives (multiple joints and nodes) in commercial metals and alloys with FCC, BCC and HCP crystal lattices, have been studied by light and electron microscopy and microdiffraction methods. It was established that special CSL, low-energy grain and phase boundaries with special physical and mechanical properties are widely spread in austenitic corrosion resistant steel 02Х18Н11 and low-alloy steels (06Х1-У, 10Г2ФБ). For the first time, presence of special low-energy grain boundaries in the structure of commercial alloy Zr1Nb has been established both theoretically and experimentally by electron microscopy and microdiffraction method. Causes of origin and evolution of special boundaries of ?=3n type and their leading role in the formation of the polycrystallinematerial structure and properties have been considered. Results were used in the development of industrial technologies for making production tubes of steel 02Х18Н11 with a guaranteed intergranular corrosion resistance; oil and gas line pipes of steel 06Х1-У characterized by a high corrosion resistance; casing tubes for fuel elements of alloy Zr1Nb, etc. The industrial technologies for production tubes of steel 02Х18Н11 with a guaranteed complex of high properties and low energy CSL grain boundaries content oil and gas line pipes of steel 06Х1-У have been introduced into production.