Selective laser melting of nano-TiB2 decorated AlSi10Mg alloy with high fracture strength and ductility. (1st May 2017)

• Record Type: Journal Article
• Authors: Li, X.P.; Ji, G.; Chen, Z.; Addad, A.; Wu, Y.; Wang, H.W.; Vleugels, J.; Van Humbeeck, J.; Kruth, J.P.
• Is Part Of: Acta materialia. Volume 129(2017)
• Page Start: 183
• Page End: 193
• Publication Date: 2017-05-01
• Subjects: Additive manufacturing -- Selective laser melting -- Aluminium alloys -- Metal matrix composites -- Mechanical properties; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2017.02.062
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: An in-situ nano-TiB2 decorated AlSi10Mg composite (NTD-Al) powder was fabricated by gas-atomisation for selective laser melting (SLM). Fully dense and crack-free NTD-Al samples were produced using SLM. In contrast to the NTD-Al powder without cell-like microstructure, the SLMed NTD-Al had a textureless microstructure, consisting of fine grains and cells, with well dispersed nano-TiB2 particles inside the grains and rod-like nano-Si precipitates inside the cells. Both nano-TiB2 particles and nano-Si precipitates exhibited a highly coherent interface with the Al matrix, indicative of a strong interfacial bonding. The formation of this microstructure was attributed to the sequential solidification of non-equilibrium and eutectic Al-Si upon rapid cooling during SLM. As a result, the SLMed NTD-Al showed a very high ultimate tensile strength ∼530 MPa, excellent ductility ∼15.5% and high microhardness ∼191 HV0.3, which were higher than most conventionally fabricated wrought and tempered Al alloys, previously SLMed Al-Si alloys and nano-grained 7075 Al. The underlying mechanisms for this strength and ductility enhancement were discussed and a correlation between this novel microstructure and the superior mechanical properties was established. This study provides new and deep insights into the fabrication of metal matrix nanocomposites by SLM from in-situ pre-decorated composite powder. Graphical abstract: Image 1