Natural aging behaviour of friction stir welded 6005A-T6 aluminium alloy

Microstructure, microhardness and corrosion susceptibility of friction stir welded AlMgSiCu alloy

“…3a. As proved in our recent work [28], the β′′ precipitate is basically coherent with Al matrix, as a result, providing strong pinning force on the moving dislocations. The decrease of microhardness in the HAZ is attributed to the full transformation from β′′ to β′ and the Q′ precipitation, forming an overaged microstructure.…”

“…round-shaped, as indicated by the rectangles and circles. As discussed in our previous work [28], the precipitates with round-shaped cross-sections are identified as the ′ (Mg 9 Si 5 [29]) phases (marked by white circles), while the rectangle-shaped precipitates with their long-axis parallelling to the <310> Al (marked by white rectangles) and <150> Al (marked by dark rectangles) directions are ′ precipitates and Q′ (Al 3.8 Cu 1.0 Mg 8.6 Si 7.0 [30]) precipitates, respectively. The corresponding SADP (as shown in Fig.…”

“…The decrease of microhardness in the HAZ is attributed to the full transformation from β′′ to β′ and the Q′ precipitation, forming an overaged microstructure. The NZ and TMAZ experienced the welding thermal cycles with high peak temperature and rapid cooling rates [28], resulting in the original β′′ precipitates dissolving in Al matrix, which increases the concentration of solute atoms in the NZ and TMAZ. Subsequently, the rapid cooling rates results in forming a supersaturated solid solution with a high concentration of vacancies.…”

Natural Aging Behavior Of Friction Stir Welded Al-Zn-Mg-Cu Aluminum Alloys

“…Even though it has been already found that high-quality, sound welds with good mechanical properties may be produced between non-weldable aluminum alloys of the 7000 series [6,7], the phenomena occurring spontaneously after welding (natural aging) in these alloys need further explanation. Some papers discussed this issue [8][9][10][11][12], however, the differences in the course of natural aging in particular alloy weldments call for additional research that provide more evidence for deeper understanding of this apparently simple phenomenon. This study concentrated on the long-term effect of natural aging (up to six years) in friction stir welds of 7136 and 7042 aluminum alloys.…”

Effect of the precipitated phase of MgZn2 on surface nanocrystallization of Al-Zn-Mg alloy based on high-frequency impacting and rolling

“…The aging strengthening, therefore, should also be paid close attention when discussing the SNC mechanism. A large of studies [13][14][15] have showed that some strengthening phases were precipitated out at the grain interior and grain boundaries after aging treatment, and the strength and hardness will be improved. But after aging strengthening treatment, what is the role of precipitated phase in the SNC process?…”