Recrystallization of iron-aluminum alloys

Conclusions In Fe–Al alloys containing up to 16% Al the grains increase in size at 1100–1200°C. The increase in grain size is one of the reasons for the poor deformability of these alloys at low temperatures, and therefore the intermediate heat treatment must be carried out at temperatures no higher than 900°C.Central Scientific Research Institute of Ferrous Metallurgy Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 6, pp. 36–38, June, 1966     

Structure and properties of titanium-free maraging alloys

The changes in the structure, phase composition, and physicomechanical properties of titanium-free maraging alloys based on the Fe-15–23% Ni-(Co, Mo, V) system after heating to the single-phase α field and two-phase α + γ field have been studied. It has been established that the strengthening of N15K10M5F5-type maraging alloys is caused by the precipitation of fine particles (20–50 nm) of intermetallic phases such as the fcc Ni₃(Mo, V) phase and the Fe₂(Mo, V) Laves phase (in the N23K9M6 alloys, with the formation of the Ni₃Mo and Fe₂Mo phases). It has been shown that the two-step aging of the N15K10M5F5 alloy leads to an additional strengthening by 200–250 MPa and provides the achievement of the ultimate tensile strength σ_u=2400?2500 MPa. The high-strength N15K10M5F5 maraging alloys are obtained with two levels of the coercive force H _c: (a) semihard maraging alloys with H _c=20?50 Oe and σ_u=2100?2400 MPa; and (b) hard magnetic maraging alloys with H _c=180?230 Oe and σ_u=1500?1800 MPa. The high-strength titanium-free N15K10M5F5 and N23K9M6 maraging alloys possess many properties characteristic of structural, elastic, and magnetic alloys and are thus multifunctional materials. These alloys can be used for advanced high-tech articles and as high-strength magnetic materials.     

Recrystallization of low-alloy Cu−Cr−Zr alloys

Conclusions To obtain the given combination of properties it is recommended that the Cu–Cr–Zr alloy be heat treated as follows: quenched from 880°, cold rolled with 90% deformation, aged at 600° for 2 h, cold worked with over 50% deformation, and annealed at 450° for 2 h.State Scientific-Research and Design Institute of Alloys and Treatment of Nonferrous Metals. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 9, pp. 53–54, September, 1979.     

Recrystallization behavior of rolled ingots of 6061 and 6069 aluminum alloys

The purpose of this study was to investigate the recrystallization characteristics of rolled, as-cast, annealed, and homogenized ingots of “Air-Slip”™ Direct Chill (ASDC) 6061 and 6069 aluminum alloys. The % R_x for annealed and homogenized 6061 and 6069 ingots is higher than that of as-cast 6061 and 6069 ingots at a given % CW and heat-treatment temperature. There is no significant difference in % R_x between annealed ingots and homogenized ingots of the same composition at a given % CW and heat-treatment temperature. The % R_x for 6069-AC ingot is higher than that of 6061-AC ingot at a given % CW and heat-treatment temperature, especially at low heat-treatment temperatures. The % R_x of annealed 6069 ingot (6069-A) and homogenized 6069 ingot (6069-H) is slightly higher than that of corresponding 6061 ingots at a given fraction % CW and heat-treatment temperature. The difference in the recrystallization behavior may be related to the increased alloy additions, in excess of the solubility, leading to relatively large second-phase particles, particularly MgSi₂. This can lead to particle-stimulated recrystallization.     

Recrystallization mechanisms during friction stir welding/processing of aluminum alloys

Restoration models for hot working of metals and alloys are reviewed in the context of their applicability to friction stir welding (FSW) and friction stir processing (FSP). Two of these models are used to interpret microstructure and microtexture data for two aluminum alloys subjected to FSP. The need for further experiments and model extensions to accommodate the transients and steep gradients in the strain, strain rate and temperature experienced by materials during FSW and FSP are discussed.     

Recrystallization of the cold-deformed discontinuous precipitation microstructure in Al-Zn (-Cu) alloys

Recrystallization of cold-rolled discontinuous precipitation microstructure which has fine laminar structure in an Al-40% Zn (atom fraction) binary alloy is investigated by optical microscopy, SEM and TEM. It is found that there are two kinds of recrystallization mechanisms: continuous coarsening (CC) and discontinuous coarsening (DC). The latter can be divided into coarsening mainly driven by stored deformation energy at colony boundaries and slip bands and the one mainly driven by boundary energy in the area with little deformation. It is shown that the addition of Cu can retard the nucleation of coarsening cells and their growth. X-Ray diffraction analysis indicated the metastable phase CuZn4 transformed into equilibrium phase Al4Cu3Zn during the heating process.     

On the structure formation in polycrystalline metals and alloys: II. Recrystallization

Effects of the difference in the thermal expansion coefficients of grains and intergranular interlayers on the process of recrystallization in metals and alloys are considered.