Impact of the Direct Ageing Procedure on the Age Hardening Response of Al-Mg-Si 6101 Alloy

Abstract

Al-Mg-Si alloys are used not only as construction material, but also as a material for electrical conductors. For this application, it is crucial for the alloy to achieve a balance between strength and electrical properties. This is achieved in practice by a combination of strain and precipitation hardening. The current paper focuses on a heat treatment procedure in which the EN AW 6101 alloy is cooled by a flowing air stream from the solutionizing temperature down to the artificial ageing temperature. The proposed procedure, unlike the common heat treatment leading to the T6 temper, allowed for the precipitation of the coarser β” phase with the presence of relatively wide precipitate-free zones. The age hardening response was investigated by Brinell hardness measurements, eddy current testing and microstructural observations using transmission electron microscopy (TEM). The applied heat treatment resulted in slightly lower strength (compared to the T6 temper), but improved electrical performance of the alloy.

Simultaneous Increase of Electrical Conductivity and Hardness of Al–1.5 wt.% Mn Alloy by Addition of 1.5 wt.% Cu and 0.5 wt.% Zr

“…Therefore, alloys of the 3xxx series are not considered as conductive, although the presence of submicron size dispersoids significantly increases the recrystallization temperature and therefore the permissible operating temperatures [8][9][10][11] compared to unalloyed aluminum. It should be noted that the interest to heat-resistant conductor alloys has increased significantly in recent years [12][13][14][15]. Their production is a difficult task since it requires the achievement of difficultly combinable properties (electrical conductivity, strength, heat resistance and high manufacturability).…”

Effects of the Mg/Si Ratio on Microstructure, Mechanical Properties, and Precipitation Behavior of Al–Mg–Si–1.0 wt %-Zn Alloys

“…Precipitation hardening of an Al–Mg–Si alloy is an ideal choice for the automobile industry because of its high strength-to-weight ratio, good formability, excellent corrosion resistance, and low cost [1,2,3]. Increased strength in alloys is acquired by paint-bake hardening after the solution is heat-treated at 560 °C and rapidly quenched to room temperature (RT) [4,5,6]. During paint-bake hardening, a large number of transition phases are formed in the matrix, resulting in a strengthening effect.…”

Review on recent progress in Al–Mg–Si 6xxx conductor alloys

“…Osuch et al [ 96 ] studied the effect of the direct aging procedure on the age-hardening response of AA6101. The procedure comprised solution treatment, followed by quenching in air down to the aging temperature and then immediate aging.…”