Analysis of Temperature Influence on Strain–Speed Parameters of Radial-Shear Rolling of Al-Zn-Mg-Ni-Fe Alloy

The comprehensive analysis of temperature influence on the strain–speed parameters of radial-shear rolling of Al-Zn-Mg-Ni-Fe alloy including the investigation of rheological properties, FEM simulation, and in-depth analytical interpretation of results was carried out. The rolling temperature has significant effect on the kinematic of metal forming, speed parameters, configuration, and length of trajectories. With the decrease in temperature, the speed of metal movement reduces, and this is the same for different components. The greatest decrease is noted for the axial speed component. In general, according to the nature of effect on the strain kinematic state, a temperature reduction of 100 °C (from 500 to 400 °C) acts similarly to a decrease in feed angle of about 4° and, in particular, increases the rolling time, nonuniformity of deformation, tightening, and temperature effect of deformation heating

Effect of Radial-Shear Rolling on the Structure and Hardening of an Al–8%Zn–3.3%Mg–0.8%Ca–1.1%Fe Alloy Manufactured by Electromagnetic Casting

Aluminum alloys are one of the most common structural materials. To improve the mechanical properties, an alloy of the Al–Zn–Mg–Ca–Fe system was proposed. In this alloy, when Fe and Ca are added, compact particles of the Al10CaFe2 compound are formed, which significantly reduces the negative effect of Fe on the mechanical properties. Because of the high solidification rate (about 600 K/s) during cylindrical ingot (~33 mm) production, the electromagnetic casting method (ECM) makes it possible to obtain a highly dispersed structure in the cast state. The size of the dendritic cell is ~7 μm, while the entire amount of Fe is bound into eutectic inclusions of the Al10CaFe2 phase with an average size of less than 3 μm. In this study, the effect of radial shear rolling (RSR) on the formation of the structure and hardening of the Al–8%Zn–3.3%Mg–0.8%Ca–1.1%Fe alloy obtained by EMC was studied. Computer simulation of the RSR process made it possible to analyze the temperature and stress–strain state of the alloy and to select the optimal rolling modes. It was shown that the flow features during RSR and the severe shear strains near the surface of the rod (10 mm) provided a refining and decrease in the size of the initial Fe-containing particles

Analysis of Microstructure Evolution of Co-Cr-Mo Alloy during Isothermal Forging

The article analyzes the microstructure evolution of Co-Cr-Mo alloy during isothermal forging. The process of isothermal forging can be a technological solution to produce a semi-finished product for subsequent deformation processing and obtain a high-quality microstructure that excludes casting defects. Based on analysis of microstructure and phase composition and calculations, the required modes of ingot homogenization are determined. Finite element method simulation of the forging has shown that temperature and deformation conditions make deformation in the single-phase γ-region possible. However, at lower temperatures, σ-phase particles may precipitate at the last steps of deformation. After isothermal forging and water quenching, a mixture of recrystallized and polygonized structures with an average grain size of 5–10 μm and precipitation of ultra-fine dispersed particles of σ-phase (~0.13 μm) at grain boundaries are formed. Isothermal forging in the temperature range of 1100–1200 °C and at low strain rates of up to 1 s−1 allows obtaining a microstructure without pores, cracks, and large inclusions. Thus, it makes it possible to use the forging billet for further deformation by different metal forming methods