Improving Thermal Stability in Cu-Containing Al-Mg-Si Alloys by Precipitate Optimization

The Correlation Between Intergranular Corrosion Resistance and Copper Content in the Precipitate Microstructure in an AA6005A Alloy

“…Cu additions to Al-Mg-Si alloys in general increase strength and thermal stability, [7,10] but often at the expense of a reduced intergranular corrosion (IGC) resistance. [11,12] Hence, this work investigates possible ways of improving IGC resistance of Cu-containing Al-Mg-Si alloys by manipulating the thermo-mechanical processes leading to the condition of the final product.…”

Precipitation in an A356 foundry alloy with Cu additions - A transmission electron microscopy study

“…The L phase is lath shaped, elongated along <001> Al with a habit plane aligning along <100> Al , and often displays a disordered structure [23,31]. L has been reported to improve thermal stability [32], and to delay overaging of the Cu-added Al-alloys. The C phase on the other hand is elongated along <001> Al , has a monoclinic unit cell, and assumes the shape of a plate [24].…”

“…However in this case, a large part of the cross sections seem to consist of single phases, see Figure 6(b) and 6(c).L-phase is recognized by the alignment of the Si-network along <100> Al throughout the precipitate cross section. This phase is closely related to Cplate, but the increased disorder causes the 0.81 nm periodicity to be broken, thus growth in the <100> Al direction is limited and the precipitates remain short instead of becoming plates[23,32].The L-phase occurs frequently in this alloy, and often contains an inver-sion center at the Si-columns in the center of the cross section, with half of the cross section shifted one {200} Al plane, perpendicular to the viewed plane. The inversion center seems common, and an example is shown in Figure7with the inversion center column marked in green.…”

Precipitate statistics in an Al-Mg-Si-Cu alloy from scanning precession electron diffraction data

“…The material studied has a nominal composition Al-1.11Mg-0.50Si-0.16Cu (at.%) [9]. From an extruded rod with cylindrical profile (Ø 20 mm) a sample of 10 mm height was cut and solution heat treated at 540 • C for 15 min, before water quenched to room temperature.…”