SPECIALITY 05.16.01 - METAL SCIENCE AND HEAT TREATMENT OF METALS
HIGHER CERTIFICATION COMMITTEE
MINIMUM PROGRAM
PhD Examination
Physicomathematical and Technical Sciences
SPECIALITY 05.16.01 - METAL SCIENCE AND HEAT TREATMENT OF METALS DIVISION OF TECHNICAL SCIENCES
Introduction
The program is based on the following disciplines: physics and chemistry of materials (metal materials), crystallography and crystal structure defects, theory and techniques of heat treatment, theory of heterogeneous media, material simulation, physical research methods, mechanical properties of metals.
The program was developed by the Expert Council of the Higher Certification Committee on Metallurgy and Metal Science of the Board of Education of the Russian Federation with participation of the Russian Tsiolkovsky Technological University.
- Structure of Metals and Alloys
- Crystal Structure and Crystal Structure Defects
- Phase and Structural Transitions in Solid Metals and Alloys
- Metallurgical Processes of Fabrication of Semifinished Materials and Products
- Heat Treatment
- Thermomechanical Treatment
- Heat Treatment Technology
- Elastic and Plastic Deformation. Failure
- Methods of Investigation and Control of Structure and Properties of Metals
- Commercial Alloys (Doping and Heat Treatment, Properties and Applications)
Main types of atomic coupling in solids. Metallic bond.
Electron structure and physical properties of metals. Fermi surface and Brillouin zones.
Substitutional, interstitial and subtractional solid solutions. Structure of electron coupling, s-phases, Laves and interstitial phases. Deviations from Vegard law.
Phase rule. Diagrams of binary and triple systems with continuous series of solid solutions, with eutectic, peritectic and monotectic equilibrium, with congruent and incongruent melting intermediate phases, with component polymorphism. Thermodynamic analysis of state diagrams. Equilibrium error in crystallization of alloys in different types of systems.
Main types of crystal lattice. Unit cells. Direction and plane indices in crystal lattice. Anisotropy of crystal properties.
Typical crystal lattices of metals. Crystallographic planes and directions with highest atom packing density in cubic and hexagonal lattices.
Types of crystal defects. Point defects. Dislocations. Stacking faults. Burgers vector. Dislocation density. Dislocation climb and dislocation glide. Generation and multiplication of dislocations, Frank-Read source. Peierls-Nabarro force. Dislocation and dislocation-impurity interaction. Dislocation networks and low angle boundaries. High angle boundaries. Twins. Crystallography and deformation twinning mechanisms.
Mechanisms of atom migration. Fick laws. Diffusion coefficient. Structure-sensitive diffusion processes. Diffusion in external force fields. Classification of phase and structural transformations. Type I and II phase transformations. Homogeneous and heterogeneous generation mechanisms. Crystallization from melt, homogeneous and heterogeneous generation of crystals. Structure and mechanism of interface motion. Shift (diffusionless) and normal (diffusion) transformation. Thermodynamic and crystallographic analysis of shift (martensite) transformation. Mechanism and kinetics of shift and normal transformation. Eutectoidal transformation. Mechanism and kinetics of eutectoidal transformation. Phase transition diagrams (thermo-kinetical, isothermal, etc.).
Solid solution ordering. Long- and short-range order. Transformation change of alloy properties. Metastable phase formation and decomposition. Decomposition of supersaturated solid solution. Spinodal decomposition. Thermodynamics of intermediate phase formation. Aging-related structural changes (clusters, Guinier-Preston zones, intermediate metastable phases, modulated structures). Coherent, partially coherent and noncoherent precipitates. Precipitate forms. Continuous and interrupted decomposition.
Casting techniques. Structure and properties of liquid metals. Homogeneous and heterogeneous nucleation of crystals, critical size of crystal nucleus. Concentration overcooling. Eutectic crystallization. Effect of crystallization rate on structure of alloys. Structure of metal ingot.
Modification of cast alloy structure. Formation of metastable phases during crystallization. Diffusionless crystallization. Metallic glasses. Formation of single crystals from melt. Grain metallurgy.
Methods of noncutting shaping (forming). Effect of temperature, scheme and degree of deformation on strain resistance, structure and properties of metals and alloys. Welding of metals and alloys. Structure and properties of welded joints.
Types of heat treatment.
Homogeneous annealing. Related changes of structure and properties of alloys.
Pre-recrystallization and recrystallization annealing. Rest. Polygonization. Primary, collective and secondary recrystallization. Mechanism and kinetics of rest, types of polygonization and recrystallization, effect of previous plastic deformation, impurities, temperature and time of annealing. Polygonized and recrystallized structure parameters. Critical degree of deformation. Recrystallization diagrams. Changes of mechanical and physical properties related to post-cold deformation annealing. Texture of deformation, primary, collective and secondary recrystallization, its mechanism. Anisotropy of properties of textured metals.
Annealing for reduction of residual stress. Mechanisms of heat-induced reduction residual stress.
Heat-induced phase transitions. Structural heredity.
Hardening without polymorphic transformation. Hardening-related changes of structure and properties. Hardening with polymorphic transformation. Martensite micro- and sub-structure. Hardening and plasticity change caused by martensite quenching. Critical cooling rate in quenching, hardenability.
Bainitic transformation. Bainite structure. Isothermal hardening.
Aging. Aging-related hardening. Effect of temperature and aging time on mechanical and physical properties of alloys. Over-aging, stepwise aging. Effect of heating-for- hardening temperature and cooling rate on structure and properties of aged alloys. Temper. Temper-induced change of microstructure, substructure and phase composition.
Reversible and irreversible temper brittleness.
Types of magnetism, their specific features. Dia- and paramagnetic metals, their position in the periodic table. Curie-Weiss law. Methods of measuring para- and diamagnetic susceptibility. Para- and diamagnetic properties of metal phases and heterogeneous alloys. Magnetic properties of ferromagnets. Magnetization curve and magnetic hysteresis cycle. Demagnetization factor notion. Methods of measuring ferromagnetic properties. Spontaneous magnetization. Nature of exchange interaction. Conditions for ferro- and anti-ferromagnetism.
Magnetic properties of solid solutions, metal phases and heterogeneous alloys. Application of magnetic analysis for study of phase equilibrium diagrams, structural transformations caused by hardening and temper, for investigation of ordering processes, etc. Requirements for phase state and microstructure of soft-magnetic and hard-magnetic alloys.
Application of magnetic and electrical methods for investigation of phase equilibrium states, microstructural changes and transformations of alloys.
Chemicothermal treatment. Thermomechanical treatment. Structural changes caused by plastic deformation. Dynamic polygonization and dynamic recrystallization. Recovery and recrystallization after hot deformation.
High- and low-temperature thermomechanical treatment. Thermomechanical treatment of precipitation hardening alloys.
Chemicoheat treatmentand related processes. Diffusion layer structure and its relation to state diagram.
Nitriding, carbonization, nitrocarburizing, calorizing, chromizing, borating, sulphurizing, silicification. Thremohydrogen treatment.
Modern equipment for hardening, annealing, temper, chemicothermal and other types of heat treatmentof steel and its alloys. Continuous annealing and hardening units. Automatization (computerization) of complete cycle of thermal treatment.
Ways of achieving high heating and cooling rates during thermal treatment. Internal stress and deformation on heat treatment. Heating in protective medium and in vacuum.
Heat-induced defects. Gasing and its effect on the structure and properties of alloys. Methods of preventing warpage and distortion.
Deformation diagrams of single crystals and polycrystals and multi-phase alloys.
Mechanisms of elastic and plastic deformation. Deformation hardening, effect of temperature and deformation rate. Yield point theory. Bauschinger effect. Hardening in solid solutions and upon excess (coherent and non-coherent) phase precipitation.
Dependence of mechanical properties on grain size. Superplasticity. Inelasticity. Brittle and viscous failure. Crack nucleation schemes. Crack propagation upon brittle and viscous failure. Nature of cold brittleness. Transition temperature (cold brittleness threshold). Fracture structure.
Creep. Creep mechanisms and stages. Stress relaxation. Short-term and long-term strength. Dependence of creep on composition and structure of alloys.
Fatigue strength. Fatigue diagrams. Fatigue mechanisms. Factors affecting fatigue strength. Contact fatigue. Wear.
Techniques of microstructure investigation. Light microscopy. Methods of quantitative metallography. Electron microscopy (replica technique, diffraction microscopy of various types of foil, scanning microscopy, microdiffraction).
X-ray structural and electron-graphic analysis. X-ray micrography spectral analysis. Local electron spectrum analysis of composition.
Methods of measuring physical properties (thermal analysis, calorimetry, dilatometry, density measurement, resistance measurement, magnetic analysis, etc.). determination of corrosion properties.
Mechanical properties of metals and alloys. Measurement techniques. Statistic and dynamic tests. Creep, long-term strength and stress relaxation tests. Fatigue tests.
Types of steel. Structural, composition and application classification of steel. Types of cast iron and their classification. Cast iron modification.
Aluminum and its alloys. Titanium and its alloys. Nickel and its alloys. Magnesium and its alloys. Refractory metal-based alloys.
Alloys with specific physical properties: high and low electrical resistance, hard magnetic and soft magnetic steels and alloys, alloys with specific elastic and thermal properties. Superconductor alloys. Shape and superelasticity memory alloys.