Effect of Ag and Cu addition on the strength and electrical conductivity of Al-Mg-Si alloys using conventional and modified thermomechanical treatments

• Published in: Journal of alloys and compounds 2022-09, Vol.914, p.165242, Article 165242
• Main Authors: Khangholi, Siamak Nikzad, Javidani, Mousa, Maltais, Alexandre, Chen, X.-Grant
• Format: Article
• Language: English
• Subjects: Ag/Cu additions; Al-Mg-Si conductor alloys; Aluminum base alloys; Conductors; Copper; Differential scanning calorimetry; Electrical conductivity; Electrical resistivity; Magnesium; Mechanical properties; Modified thermomechanical treatment; Silicon; Silver; Thermomechanical analysis; Thermomechanical properties; Thermomechanical treatment; Transmission electron microscopy
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2022.165242

The effect of adding Ag and Cu on the strength and electrical conductivity of Al-Mg-Si conductor alloys was investigated using conventional and modified thermomechanical treatments. In the conventional thermomechanical treatment, the addition of Ag and Cu moderately increased the strength from 296 MPa to 305–316 MPa above the minimum required electrical conductivity (52.5% IACS) compared to that of the base alloy. However, the modification of the thermomechanical treatment could maximize the efficiency of Ag and Cu addition at strengths above 52.5% IACS, exhibiting that the strength was increased from 317 MPa to 341–348 MPa with the Ag and Cu additions. All alloys under the modified thermomechanical treatment (MTMT) showed a superior strength and electrical conductivity compared to their counterparts under the conventional thermomechanical treatment (CTMT), resulting in a wider window in the high end of strength and electrical conductivity. In addition, MTMT led to a shorter post-aging time to reach the minimum required EC, compared to CTMT. The precipitate characteristics under both thermomechanical treatment conditions were analyzed and quantified using differential scanning calorimetry and transmission electron microscopy (TEM). The TEM results revealed that the alloys under MTMT had a higher precipitate number density by more than three times compared to their counterparts under CTMT, leading to the higher strength levels in the MTMT alloys. Strength and electrical resistivity models were then applied to understand the multiple contributions of the main strengthening mechanisms and microstructure features to the mechanical strength and electrical conductivity. •Modified thermomechanical treatment is proposed to enhance both strength and electrical conductivity (EC).•The effects of Ag and Cu additions on the strength and EC in Al-Mg-Si conductor alloys are studied.•The efficiency of the Ag and Cu additions is maximized using the modified thermomechanical treatment in terms of strength and EC.•The strength and electrical resistivity models are applied.