The influence of hybrid rate on the microstructure and mechanical properties of AlSi10Mg composites fabricated via SLM

Abstract

In this study, the nano MgO particles and multi-walled carbon nano tubes (MWCNTs) are inserted into AlSi10Mg matrix, and the composites are produced via selective laser melting (SLM) method. The composite comprises of AlSi10Mg, and mixing of 0.005 wt.%, 0.010 wt.%, and 0.020 wt.% of MgO and MWCNTs. The microstructure of the SLMed composites is examined with optical and scanning electron microscope. It is revealed that intermetalics and the supersaturated primary α-Al structure which increases the strain hardening, surrounded by interconnecting fibrous Si phase which then were transformed to a coarse eutectic structure that tends to be less stiff. The mechanical behaviors are analyzed by tensile, hardness and nanoindentation tests, finally the fracture surfaces of the used specimens are studied via scanning electron microscope (SEM). The tensile strength value of the SLMed AlSi10Mg materials increased from 405 to 559 MPa. Best strength-ductility pattern with maximum tensile strength (559 MPa), yield strength (253 MPa) and elongation (5.9%) is obtained, that is comparable and superior to the Alsi10Mg alloy. The tensile test fracture surfaces of the composites showed a clear mode of the ductile fracture. Additionally, the hardness of AlSi10Mg alloy rose from 85 to 137 HV. In the nanoindentation test, Doerner and Nix, Oliver and Pharr, and Suresh models for hardness were used. Among the three models, the lower error percentage was seen in the Suresh model which contributed to obtaining the best results. Young’s modulus of AlSi10Mg improved by 3.39%, 8.97%, and 12.93% with reinforcement content of 0.005 wt.%, 0.010 wt.%, and 0.020 wt.%, respectively.