Effect of iron content on the structure and properties of Al4Ca0.8Mn(0.5, 1.3)Fe (wt%) alloy after high-pressure torsion

• Published in: Materials characterization 2024-07, Vol.213, p.114019, Article 114019
• Main Authors: Rogachev, S.O., Naumova, E.A.
• Format: Article
• Language: English
• Subjects: Aluminum alloy; Electrical conductivity; High-pressure torsion; Intermetallic compounds; Mechanical properties; Microstructure; Segregations; Severe plastic deformation
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2024.114019

The advantages of the Al–Ca–Mn–Fe alloys are their lightness, good ductility, high corrosion resistance, and excellent casting properties, but the main disadvantage is their low strength. Therefore interest in current work lies in improving the strength properties of these alloys though the severe plastic deformation method. The Al–4Ca–0.8Mn–(Fe) eutectic-type alloys with an iron content 0.5 and 1.3 wt% were processed by severe plastic deformation using the high-pressure torsion technique (HPT). HPT of the 20-mm diameter samples was carried out at room temperature through three revolutions. To characterize the samples we used the microstructural studies by an optical microscope, scanning microscope, and transmission microscope, the microhardness measurements, the hardening's thermal stability analysis, the tensile tests, and the electrical conductivity measurements. It was found that as a result of HPT, a bimodal, but predominantly nanocrystalline microstructure was formed in the alloys and a simultaneous improvement in strength (4–6.5 times) and relative elongation (1.1–1.7 times) was achieved while maintaining a moderately low electrical resistance. Increasing the iron content from 0.5 to 1.3 wt% in the alloy provides a smaller grain size and a higher level of strength after HPT. The microstructural mechanisms of increasing strength and ductility in the alloys with different iron content are discussed. The effect of post-processing annealing on the mechanical properties of the alloys was studied. •The Al–4Ca–0.8Mn–(0.5, 1.3)Fe (wt%) alloy was processed through HPT•A bimodal nanocrystalline structure with a low density of intracrystalline defects is formed.•Increasing the iron content from 0.5 to 1.3 wt% provides a smaller grain size and a higher strength.•HPT increases both strength and ductility.•900 MPa-ultimate tensile strength and 3%-relative elongation were achieved.