Microstructural evolution of AA7050 al alloy processed by ECAP (original) (raw)

High Strength AA7050 Al alloy processed by ECAP: Microstructure and mechanical properties

Materials Science and Engineering: A, 2011

Commercial AA7050 aluminium alloy in the solution heat-treated condition was processed by ECAP through routes A and B C . Samples were processed in both room temperature and 150 • C, with 1, 3, and 6 passes. The resulting microstructure was evaluated by optical microscopy (OM) and transmission electron microscopy (TEM). Only one pass was possible at room temperature due to the low ductility of the alloy under this condition. In all cases, the microstructure was refined by the formation of deformation bands, with dislocation cells and subgrains inside these bands. The increase of the ECAP temperature led to the formation of more defined subgrain boundaries and intense precipitation of spherical-like particles, identified as Á and Á phases. After the first pass, an increase in the hardness was observed, when compared with the initial condition. After 3 passes the hardness reached a maximum value, higher than the values typically observed for this alloy in the overaged condition. The samples processed by route B C evolved to a more refined microstructure. ECAP also resulted in significant strength improvement, compared to the alloy in the commercial overaged condition.

Investigation of Microstructural and Hardness Changes of AA7075 Alloy Processed by Ecap

Mühendislik bilimleri ve tasarım dergisi, 2021

This study aims to examine the change in microstructural and hardness values AA7075 aluminum alloy, which is frequently preferred in the aviation industry by applying the Equal Channel Angular Pressing (ECAP) method. ECAP method, one of the plastic deformation methods, has been successfully carried out by applying 0.025mm/sec pressing speed and 200°C temperature for a different route (A, Bc, C) and the different number of passes (2, 4, 8). The characterization of the aluminum alloy obtained by applying ECAP process was carried out by optical microscope (OM), X-ray diffraction (XRD), and scanning electron microscope (SEM) analysis. Hardness tests have been applied to examine the mechanical properties of the material. The microstructures of the materials obtained as a result of the application were examined. It was observed that precipitation occurred in the AA7075 alloy depending on the applied temperature, pressing, and grain breakage. Moreover, it is seen that the grain size of the materials produced by the ECAP method has been reduced, and consequently the strength of the material increases. As a result of the ECAP process, it was seen that the existing phases were α-Al, -MgZn2, S-Al2CuMg, and Al7Cu2Fe. The grain size of 288.4 nm obtained after 8 repeated passes using the Bc route was the smallest grain size obtained.

Evolution of the AA2030 alloy microstructure in the ECAP process

Kovove Materialy-Metallic Materials

This work aims to study the microstructural development of lead-containing aluminum alloy in the process of intense plastic deformation. The evolution of the AA2030 alloy obtained by the ECAP and long-term natural aging (within 45 months) has been analyzed using electron microscopes. The average grain size of the ECAP treated samples is 420 and 380 nm along the routes Bc and C, respectively. Long-term natural aging contributes to transforming grain boundaries without changing their size. The results have shown that the structure, phase distribution, and stoichiometric composition of the inclusions differ significantly during annealing, equal-channel angular pressing, and long-term natural aging. The strain route affects the dissolution kinetics and evolution of inclusions. A mechanism for refining the grains is proposed that is associated with high dislocation density, dislocation cells, grain and subgrain boundaries, as well as the evolution of inclusions in the ECAP AA2030 alloys.