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The morphology, chemical composition and formation mechanism of non-metallic inclusions in magnetic alloy of Fe-Co-Ni-Cu-Al-Ti-Hf system were investigated. These alloys are used in manufacturing single-crystal permanent magnets. Modern methods for the identification of non-metallic inclusions, as well as computer simulation of the processes of their formation by Thermo Calc software were used in the work. It was found that studied alloy contains (Ti, Hf)S titanium and hafnium sulfides, (Ti, Hf)2SC titanium and hafnium carbosulfides, Ti2O2S titanium oxisulfide, HfO2 hafnium oxide, and Al2O3 aluminum oxide. No titanium and hafnium nitrides were found in the alloy. The bulk of nonmetallic inclusions are (Ti, Hf)2SC carbosulfides and (Ti, Hf)S sulfides. All carbides and many oxides are within carbosulfides and sulfides. When the sulfur content in the alloy is no more than 0.2%, and carbon content does not exceed 0.03%, carbosulfides are formed in the solidification range of the alloy and has an faceted compact form. If the sulfur content in the alloy becomes more than 0.2% and carbon content more than 0.03%, the carbosulfide formation begins before the alloy solidification or at the begining stages of solidification. In this case, carbosulfides are dendritic and coarse. Such carbosulfides actively float in the solidified melt and often come to the surface of the castings. In this case, specific surface defects are formed in single-crystal magnets, which are called sulfide stains. All titanium and hafnium sulfides are formed at the lower part of solidification range and have elongated shape. [ABSTRACT FROM AUTHOR]

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Abstract: As a result of numerical and experimental investigation of the influence of friction forces on the dynamic strain of elastoviscoplastic samples (pellets), the main regularities of their formation have been established for metals and alloys. A new method of identification of the dry friction coefficients (according to Coulomb) on each contact surface depending on the formings of the lateral surface of the pellets is proposed; it is based on the numerical simulation of the axisymmetric dynamic problem and the rapidly convergent method of successive approximations. As a result, dynamic stress-strain diagrams are built taking into account the friction forces and radial inertia. [ABSTRACT FROM AUTHOR]

The modification of the one-parameter numerical continuation method for studying the dynamics of vibroimpact systems subject to periodic external loads is proposed. The behavior of a vibroimpact double spring mass system with two degrees of freedom is analyzed in relation to the load intensity. Specific applications of the method are compared with the two impact simulation procedures: contact force on the basis of the Hertz quasistatic theory and boundary conditions using the coefficient of restitution based on the stereomechanical theory of impact. Numerical analysis results for dynamic system states with the two impact simulation procedures are presented. [ABSTRACT FROM AUTHOR]

The finite-element-analysis-based computational system of ProCAST is used for computer modeling of the production of an ingot and its piercing on a press. The results are then recoded for the finite-element computing environment of DEFORM-3D, which is used to model the piercing of the ingot on the press. The effect of the deformation the ingot during piercing on the change in the density of the metal that is being shaped is determined. The feasibility and prospects of using ProCAST and DEFORM 3D together are discussed. [ABSTRACT FROM AUTHOR]

Possibilities of the semi-analytical finite element method in the investigation of transient processes of the three-dimensional deformation of heterogeneous bodies of revolution and complex-shaped prismatic bodies by the action of pulsed stressing with allowance for contact interaction zones and nonlinear work of material are shown by calculations of real structures. [ABSTRACT FROM AUTHOR]

On the basis of a semi-analytical finite element method, an effective approach has been developed for studying transient processes of dynamic deformation of three-dimensional heterogeneous bodies of revolution and prismatic bodies of complex shape and structure by the action of time-and space-varying pulsed stressing with allowance for the plastic properties of the material and time-varying contact interaction conditions. New types of finite elements have been created, on the basis of which computational relationships of the semi-analytical finite element method (SAFEM) for problems of dynamics have been constructed. Modified relationships of the Newmark method have been obtained, which have been formulated for the amplitude subsystems of SAFEM. Effective block iteration algorithms for the solution of large systems of nonlinear equations of SAFEM have been developed and realized. [ABSTRACT FROM AUTHOR]