Additive manufacturing and mechanical properties of the dense and crack free Zr-modified aluminum alloy 6061 fabricated by the laser-powder bed fusion

The heterogeneous microstructure in an Al-Zn-Mg-Cu-Sc-Zr alloy produced by selective laser melting

“…With the formation of fine heterogeneous microstructure, cracks and pores are also reduced significantly and even eliminated. The elimination of these defects is considered to relate to the formation of heterogeneous microstructures, which effectively disperses stresses generated during the thermal cycling process [18]. The formation of fine heterogeneous microstructures is expected to improve the mechanical properties of the alloys fabricated by SLM.…”

Optimization of the strength vs. conductivity trade-off in an aluminium alloy designed for laser powder bed fusion

“…To make the 6061 alloy processable by PBF-LB, a pre-alloyed powder of a standard 6061 was gas atomized but with a substantial addition of Zirconium, about 2.3 wt. %, twice more than in the work of Mehta [27] and Opprecht [17]. This alloy will be qualified as a Zr-modified 6061 alloy in the subsequent sections.…”

“…This critical Zr content is likely to differ if a pre-alloyed powder was to be loaded into the PBF-LB machine instead. Indeed, the recent work of Mehta et al [27] suggests that introducing 1 wt.% of Zr is enough to overcome hot cracking issues when using a building substrate maintained at 100°C. The powder batch was atomized under Ar by Nanoval®.…”

“…Such a strategy is also promising because the processing conditions typical of PBF-LB can be exploited to achieve supersaturated solid solutions that can be further heat-treated to increase the mechanical strength while increasing the electrical or thermal conductivity. Introducing Zr in heritage Al alloys to improve their processability via AM has already been proposed in the literature, see examples on 5XXX [26], 6XXX [13,27], or 7XXX series [28]. Mehta et al [27] reported successful attempts to produce crack-free samples in a Zr-modified 6061 (addition of 1 wt.% Zr).…”

“…Introducing Zr in heritage Al alloys to improve their processability via AM has already been proposed in the literature, see examples on 5XXX [26], 6XXX [13,27], or 7XXX series [28]. Mehta et al [27] reported successful attempts to produce crack-free samples in a Zr-modified 6061 (addition of 1 wt.% Zr). The same authors have also investigated the tensile properties of the as-fabricated microstructure as well after a T6 sequence but the microstructure-property relationships have been poorly addressed, in particular functional properties were not investigated.…”