Aging temperature effects on microstructure and mechanical properties for additively manufactured AlSi10Mg

Abstract

AlSi10Mg alloy was prepared by laser powder bed fusion (LPBF). The evolution of microstructure and mechanical properties after diverse aging temperatures were systematically studied. The metastable ultra-fine cellular structure was obtained for as-built specimens. Aging at lower temperatures (100–225°C) promotes the formation of a large number of Si-rich precipitates, and the original Si networks can be retained. With the increase in aging temperature, Si network gradually broke apart, and Si-rich particles grew and spheroidised. The hardness increases with temperatures up to 175°C, and decreases thereafter, while the opposite trend was observed for elongation. Excellent comprehensive mechanical properties with a tensile strength of 381 MPa and elongation of 5.2% can be obtained at 225°C for 2 h. Highlights The effect of aging temperatures on microstructure stability and mechanical properties of additive manufacturing AlSi10Mg alloy has been revealed systematically. The Si-rich precipitates and eutectic Si network were responsible for the observed mechanical properties changes. A good combination of strength and ductility is obtained at 225°C for 2 h aging heat treatment.

Revealing the strengthening contribution of stacking faults, dislocations and grain boundaries in severely deformed LPBF AlSi10Mg alloy

“…4 d–f. This statement finds support in the findings from reference 24 , which showed that adjacent cells within a single grain possessed closely matched crystallographic orientations, with misorientation angle about 0.6°. Moreover, a comparison between the cell and grain structures reveals that the cell size is at least one order of magnitude smaller than the grain boundary size (see the green dashed line in Fig.…”

Influence of Ni Contents on Microstructure and Mechanical Performance of AlSi10Mg Alloy by Selective Laser Melting

“…The high tensile strength of the 1Ni- and 3Ni-AlSi10Mg samples should be due to their fine Si networks, as shown in Figure 9 c. Chen et al [ 29 ] and Zhao et al [ 30 ] demonstrated the effectiveness of the Si network in hindering dislocation movement and identified the Orowan looping as the dominant strengthening mechanism for AlSi10Mg alloys. During the deformation process, the dislocation could be pinned by the nanosized Si particles at the Si network boundaries, which activated the Orowan mechanism and produce a strong strain-hardening effect [ 31 ]. The refined Si network in the 3Ni-AlSi10Mg sample reduced the distance between Si particles, which can reduce the dislocation movement and achieve a higher tensile strength than the 1Ni-AlSi10Mg sample.…”

Investigation of the Effects of Various Severe Plastic Deformation Techniques on the Microstructure of Laser Powder Bed Fusion AlSi10Mg Alloy

“…~0.36 µm. Since the LPBF microstructure was highly metastable [37], it continued to evolve during the heat treatment process. As shown in Figure 5b,c, the cells in the annealed samples were coarser than the as-built sample.…”