Cabrini Marina, Lorenzi Sergio, Testa Cristian, Manfredi Diego, Lombardi Mariangela, Aversa Alberta, Andreatta Francesco, Fedrizzi Lorenzo, Dekhtyar Yuri, Sorokins Hermanis, Pastore Tommaso
Department of Engineering and Applied Sciences, School of Engineering, University of Bergamo, 24044 Dalmine (BG), Italy.
Research Unit of Bergamo of National Interuniversity Consortium of Materials Science and Technology (INSTM), 24044 Dalmine (BG), Italy.
Materials (Basel). 2021 Sep 27;14(19):5602. doi: 10.3390/ma14195602.
The paper deals with the evolution of the microstructure of AlSi10Mg alloy obtained by laser powder bed fusion (LPBF), as a function of the post-processing heat treatment temperature. This was approached by complementary methods including FE-scanning electron microscopy, scanning Kelvin probe force microscopy and exo-electron emission techniques. The fast cooling rate of the LPBF process as compared to traditional casting produces a very fine microstructure with high mechanical properties and corrosion resistance. However, the LPBF-AlSi10Mg alloy can be susceptible to selective corrosion at the edge of the melt pools generated by the laser scan tracks. Post-process thermal treatments of the Al alloy induce a marked modification of the silicon network at melt pool edges, in particular at high temperature such as 400 °C. It was found that this is associated to a more homogeneous distribution of Volta potential. Analysis of exo-electron emission confirms the silicon diffusion during thermal treatment. The modification of the silicon network structure of the LPBF-AlSi10Mg during thermal treatment reduces the susceptibility to selective corrosion.
本文研究了激光粉末床熔融（LPBF）制备的AlSi10Mg合金微观结构随后处理热处理温度的演变。这是通过包括场发射扫描电子显微镜、扫描开尔文探针力显微镜和外电子发射技术在内的互补方法来实现的。与传统铸造相比，LPBF工艺的快速冷却速率产生了具有高机械性能和耐腐蚀性的非常精细的微观结构。然而，LPBF-AlSi10Mg合金在激光扫描轨迹产生的熔池边缘可能易受选择性腐蚀。铝合金的后处理热处理会引起熔池边缘硅网络的显著变化，特别是在400°C等高温下。研究发现，这与更均匀的伏打电位分布有关。外电子发射分析证实了热处理过程中的硅扩散。热处理过程中LPBF-AlSi10Mg合金硅网络结构的改变降低了对选择性腐蚀的敏感性。
