| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Additive Manufacturing: Processing Effects on Microstructure and Material Performance
|
| Presentation Title |
A-93: Critical Quenching Rates After Solution Annealing: Peculiarities of Aluminum-silicon Alloys Fabricated by Laser Powder-Bed Fusion |
| Author(s) |
Stephan Hafenstein, Leonhard Hitzler, Enes Sert, Andreas Öchsner, Markus Merkel, Ewald Werner, Jonas Von Kobylinski |
| On-Site Speaker (Planned) |
Jonas Von Kobylinski |
| Abstract Scope |
The microstructural characteristics of selective laser melted aluminium-silicon alloys differ vastly from their respective cast counterparts. The high cooling rates lead to an increased (non-equilibrium) solubility of Si in α-Al and consolidates in a cellular structure starting from the melt pool boundaries. Correspondingly, the Si-content is inhomogeneous across a single scan track, with the Si-content decreasing from the scan track boundaries towards its center. Si-segregations occur in these oversaturated regions and this enrichment is further escalated in remolten areas. When left untreated, these Si-enrichments represent brittle areas and predetermined locations of fracture. Efforts to overcome these segregations by means of post-heat-treatments, including a solution annealing step, were successful to dissolve the segregations, but at the cost of lowering the mechanical strength. Interestingly, the quenching rate of SLMed AlSi after solution annealing seemed to impact the effectiveness of the subsequent artificial aging, which is unknown for cast AlSi. |
| Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |