Zhenhua Fan,Xingchen Yan,Zhiyong Fu,Ben Niu,Junfu Chen,Yongjun Hu,Cheng Chang,Jianglong Yi
In this present work, a novel electrostatic self-assembly method was invented to produce AlSi10Mg powders homogeneously decorated with TiC nanoparticles . The TiC/AlSi10Mg alloy with homogenous, crack-free, equiaxed and super fine-grained were produced using selective laser melting (SLM). The in-situ formation of D0 22 -Al 3 Ti created by TiC and Al matrix during SLM was revealed at the first time and both TiC and D0 22 -Al 3 Ti nanoparticles were extremely effective inoculant for an SLMed AlSi10Mg alloy. Therefore, the SLMed TiC/AlSi10Mg alloy exhibited a high tensile strength (ultimate tensile strength ~ 456 MPa, yield strength ~338 MPa) and high microhardness (131 HV 0.05 ), which were higher than the SLMed AlSi10Mg alloy (ultimate tensile strength ~437 MPa, yield strength ~254 MPa and microhardness ~113 HV 0.05 ). This study can be regarded as a guidance in the fabrication of metal matrix nanocomposites using for SLM.
To enhance the long-term corrosion resistance of 3D-printed AlSi10Mg alloy, this work designed a two-step micro-arc oxidation (MAO) strategy. Given the difficulty of triggering micro-arc discharge in high-Si Al alloys, an intermediate transition layer was first prepared through one-step MAO in a silicate electrolyte. Subsequently, a two-step MAO treatment was performed in a phosphate electrolyte with the addition of K 2 ZrF 6 to seal the ablation holes formed during the one-step MAO process, achieving a self-sealing effect of the MAO coating. Ultimately, a dense ZrO 2 /Al 2 O 3 ceramic coating with Si-W-Zr-P gradient distribution was obtained on the AlSi10Mg surface after the two-step MAO. Electrochemical tests reveal that the two-step MAO coating exhibits exceptional corrosion resistance, with a remarkably low corrosion current density (I corr ) of 3.42 × 10 −9 A·cm −2 , along with a protective efficiency (η p ) of up to 99.8 %. Moreover, no obvious macroscopic corrosion signs are observed on the ZrO 2 /Al 2 O 3 coating after prolonged immersion, and its I corr remains stable at 9.26 × 10 −9 A·cm −2 , indicating durable protective performance. This study offers a novel and controllable strategy for the design of anti-corrosive coatings on 3D-printed high-Si Al alloys.
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