Comparative investigation of microstructure, mechanical properties and strengthening mechanisms of Al-12Si/TiB2 fabricated by selective laser melting and hot pressing. Issue 15 (15th October 2018)

• Record Type: Journal Article
• Authors: Xi, L.X.; Zhang, H.; Wang, P.; Li, H.C.; Prashanth, K.G.; Lin, K.J.; Kaban, I.; Gu, D.D.
• Is Part Of: Ceramics international. Volume 44:Issue 15(2018)
• Page Start: 17635
• Page End: 17642
• Publication Date: 2018-10-15
• Subjects: Selective laser melting -- Al-12Si/TiB2 -- Hot pressing -- Wetting behavior -- Microstructure and mechanical properties -- Strengthening mechanisms; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2018.06.225
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Near-fully dense Al-12Si matrix composites reinforced with TiB2 ceramic particles (2 wt%) were successfully fabricated by selective laser melting (SLM) and hot pressing (HP) of powder mixtures. TiB2 ceramic particles are homogeneously distributed in the Al-12Si matrix at the micrometer-scale owing to a very good wetting between molten Al-12Si alloy and TiB2 ceramic. The microstructural analysis of the as-fabricated SLM samples show the formation of a supersaturated α-Al phase and the decrease of free residual Si with respect to the hot-pressed ones. Both composites exhibit a fine microstructure with a grain size of ~ 5.1 µm and ~ 5.8 µm for SLM- and HP-fabricated samples with addition of TiB2 ceramic particles. The SLM Al-12Si/TiB2 composite exhibits significantly improved microhardness (~ 142 ± 6.0 HV0.05 ) and yield strength (~247 ± 4.0 MPa) compared to the corresponding HP one. Fine cell morphology and nanostructured dispersion strengthening are responsible for the improved mechanical strength of the Al-12Si/TiB2 composite processed by SLM.