Solidification cracking susceptibility of high strength aluminum alloy weldment

Evolution of microstructure and mechanical properties in naturally aged 7050 and 7075 Al friction stir welds

“…The high strength aerospace Al alloys, namely 7050 and 7075, are considered "unweldable" by fusion techniques due to solidification cracking or severely degraded mechanical properties within the joint [13,14]. In contrast, solid-state FSW produces joints without recast material thereby eliminating issues with solidification cracking and weld defects.…”

Investigating the effects of traveling speeds and post-weld heat treatment on mechanical properties of nano-Al2O3-fortified AA6061-T6 friction stir welds

“…Thanks to their low density, high strength to weight ratio, and excellent corrosion resistance, the heat treatable aluminum 6xxx (Al-Mg-Si) alloys are appropriate materials for marine, aerospace, and automotive industries. 1–3 Besides, aluminum 6xxx-T6 has excellent mechanical properties because of various shapes of precipitates. 4 The variation of mechanical behavior of Al 6061 is due to metallurgical phenomena such dissolution, growth, and coarsening of precipitates.…”

Precipitate microstructures and resulting properties of Al-Zn-Mg metal inert gas-weld heat-affected zones

“…Medium strength 7xxx aluminum alloys (based on the Al-Zn-Mg system) have a good combination of properties making them suitable for many automotive applications where high specific mechanical properties are required. Besides solidification cracking susceptibility of the weld fusion zone, [1][2][3][4][5] the properties of the base material are also weakened outside the fusion zone due to the thermal cycle experienced in the so-called heat-affected zone (HAZ), [6] due to modifications in the precipitate microstructure, which is responsible for the major contribution to the yield strength. [7][8][9][10] When this is technologically feasible, one way to erase the welding history in the HAZ, i.e., to recover a structure with homogeneous properties after the welding process, is to proceed with post-welding heat treatments (PWHTs) either by natural aging [7] or by subsequent artificial aging.…”