Optimization of Strength‐Electrical Conductivity Properties in Al–2Fe Alloy by Severe Plastic Deformation and Heat Treatment

• Published in: Advanced engineering materials Vol. 20; no. 3
• Main Authors: Medvedev, Andrey E, Murashkin, Maxim Y, Enikeev, Nariman A, Valiev, Ruslan Z, Hodgson, Peter D, Lapovok, Rimma
• Format: Journal Article
• Language: English
• Published: 01-03-2018
• Subjects: Al–Fe alloys; Annealing; Electrical conductivity; High‐pressure torsion; Hot deformation; Mechanical strength
• ISSN: 1438-1656; 1527-2648
• DOI: 10.1002/adem.201700867

High‐pressure torsion at room temperature followed by two processing routes, either 1) annealing at 200 °C for 8 h or 2) elevated temperature (200 °C) high‐pressure torsion, are employed to obtain simultaneous increase in mechanical strength and electrical conductivity of Al–2 wt%Fe. The comparative study of microstructure, particle distribution, mechanical properties, and electrical conductivity for both processing routes gives the optimal combination of high mechanical strength and high electrical conductivity in Al–2Fe alloy. It is shown that while the mechanical strength is approximately the same for both processing routes (>320 MPa), high‐pressure torsion at elevated temperature results in higher conductivity (≥52% IACS) due to reduction of Fe solute atom concentration in Al matrix compared to annealing treatment. High‐pressure torsion at 200 °C has been demonstrated as a new and effective way for obtaining combination of high mechanical strength and electrical conductivity in Al–Fe alloys.
The dynamic aging of UFG Al–Fe alloy (HPT at 200 °C) has been used to enhance the electrical conductivity. Comparison of observed results with static aging (annealing at 200 °C for 8 h), also performed in present work, shows superiority of dynamically aged alloy over statically aged. The increase of electrical conductivity by ≈3% IACS is accompanied by substantial decrease of heat treatment time from 8 h for static annealing to 5 min for high temperature deformation.