Cerium Effect on the Phase Composition and Crystallization Behavior of Aluminum Casting Alloys Based on the Al–Mg–Si System

Russian Journal of Non-Ferrous Metals - Using a Thermo-Calc software package (TCAl4.0 database), unexplored data concerning the phase composition and crystallization behavior of...     

Processability and Structure Formation of the Al–Zn–Mg–Ca–Fe–Zr–Sc Alloy upon Hot Rolling and TIG Welding

Russian Journal of Non-Ferrous Metals - Technological regimes for producing wrought products (2 and 1 mm) from the Al–4.5%Zn–2.5%Mg–2.5%Ca–0.5%Fe–0.2%Zr–0.1%Sc...     

Thermographic study of the contact melting of metals. II. Binary systems with intermediate phases

Differential thermal analysis, metallography, and local x-ray spectral analysis were used to study the heat effects and structural changes occurring upon heating powder mixtures of pairs of elements whose binary phase equilibrium diagrams contain one or more intermediate phases. It was found that contact melting in these mixtures is accompanied by exothermal heat effects in both the solid and liquid states, related to the formation of intermetallic compounds. The temperatures at which strong exothermal effects were observed coincide with the melting temperatures of eutectics in the various systems. The magnitudes of the heat effects are determined by the differences between the exothermal heats of formation of the intermediate phases and the endothermal heats of formation of the liquid phases which formed simultaneously. In the systems containing phosphorous, interaction was controlled by the sublimation of this component. Phosphides were formed at low temperatures as a result of the rapid exothermal reaction of phosphorous vapor with the metals.Institute of Metal Physics, National Academy of Sciences of the Ukraine, Kiev. Translated from Poroshkovaya Metallurgiya, Nos. 7–8, pp. 114–123, July–August, 1994.     

Influence of annealing on electrical resistance and hardness of hot-rolled aluminum alloy sheets containing up to 0.5% Zr

We investigated the influence of multistep up to 650°C on the magnitude of resistivity and hardness of hot-rolled sheets of low-alloyed aluminum alloys containing up to 0.5 wt % Zr. Experimental samples were formed in conditions approaching those implemented for industrial installations of continuous casting and rolling. Testing procedures, including heat treatment, are described. Metallographic analysis of a cast (initial) structure and the structure of experimental samples passing the deformation was performed. Dependences of resistivity (ρ) and hardness on the temperature of the last annealing step are constructed by the results of physicomechanical tests. It is established using the computational and experimental methods that the magnitude of ρ mainly depends on the zirconium concentration in the aluminum alloy. The optimal ratio between the zirconium concentration in the alloy and annealing temperature, which makes it possible to attain the best combination of characteristics of hardness and resistivity, is determined.     

Effect of Radial Shear Rolling on the Structure and Mechanical Properties of a New-Generation High-Strength Aluminum Alloy Based on the Al – Zn – Mg – Ni – Fe System

Metal Science and Heat Treatment - A high-strength aluminum alloy based on the Al – Zn – Mg – Ni – Fe system is studied in deformed condition after radial shear rolling with...     

Novel High-Strength Casting Al−Zn−Mg−Ca−Fe Aluminum Alloy without Heat Treatment

Russian Journal of Non-Ferrous Metals - Based on the studies of its structure, as well as technological and mechanical properties, the composition and application prospects are substantiated for a...     

Effect of a high temperature and hydrostatic pressure on the structure and the properties of a high-strength cast AM5 (the 201.2 alloy type) aluminum alloy

The phase-transition temperatures of a high-strength cast AM5 aluminum alloy are determined at atmospheric pressure and an excess pressure of 100 MPa using differential barothermic analysis (DBA) and classical differential thermal analysis (DTA). An excess pressure of 100 MPa is shown to increase the critical temperatures of the alloy by 12–17°C (including an increase in the solidus temperature by 12°C), which makes it possible to increase the hot isostatic pressing (HIP) temperature above the temperature of heating for quenching. The following three barothermal treatment schedules at p = 100 MPa and τ = 3 h, which have different isothermal holding temperatures, are chosen to study the influence of HIP on the structure and the properties of alloy AM5 castings: HIP1 (t₁ = 505 ± 2°C), HIP2 (t₂ = 520 ± 2°C), and HIP3 (t₃ = 540 ± 2°C). High-temperature HIP treatment is found to increase the casting density and improve the morphology of secondary phases additionally, which ensures an increase in the plasticity of the alloy. In particular, the plasticity of the alloy after heat treatment according to schedule HIP3 + T6 (T6 means artificial aging to achieve the maximum strength) increases by a factor of ～1.5.     

Formation of the structure of thin-sheet rolled product from a high-strength sparingly alloyed aluminum alloy “nikalin”

The regime of thermomechanical treatment of flat ingots of a high-strength sparingly alloyed alloy based on the Al–Zn–Mg–Ni–Fe system upon the production of thin-sheet rolled products with a reduction of more than 97% has been substantiated. Using experimental and calculated methods, the structure and phase composition of the experimental alloy in the as cast and deformed state and after heat treatment including quenching with subsequent aging have been studied. It has been found that the structure of the wrought semi-finished products after aging according to Т and Т1 regimes consists of the precipitation-hardened aluminum matrix and uniformly distributed isolated particles of Al₉FeNi with a size of 1–2 μm, which provides a combination of high strength and satisfactory plasticity at the level of standard high-strength aluminum alloys of the Аl–Zn–Mg–Cu system. The fractographic analysis confirmed that the tested samples underwent a ductile fracture.     

Thermodynamics of the Effect of Alloying of Phase Formation during Crystallization of Aluminum Matrix Composites with Exogenous Reinforcement

Russian Journal of Non-Ferrous Metals - A thermodynamic assessment of the influence of alloying elements (Si, Mg, Cu, Ti) on the processes of phase formation during the production and liquid-phase...