Fabrication condition greatly influences the microstructures and properties of Al alloys. However, most of the available reports focus on a single fabrication technique, indicating there is still a lack of systematic comparisons among wider ranges of fabrication methods. In this paper, with conventional casting (via sand/Fe/Cu mold) and additive manufacturing (AM, via selective laser melting, SLM) methods, the effects of cooling rate (Ṫ) on the microstructures and mechanical properties of hypoeutectic Al-10Si-0.5Mg alloy are systematically investigated. The results show that with increasing cooling rate from sand-mold condition to SLM condition, the grain size (d) is continuously refined from ~3522 ± 668 μm to ~10 μm, and the grain morphology is gradually refined from coarse dendrites to a mixed grain structure composed of columnar plus fine grains (~10 μm). The eutectic Si particles are effectively refined from blocky shape under sand/Fe-mold conditions to needle-like under Cu-mold conditions, and finally to fine fibrous network under SLM condition. The tensile yield strength and elongation is greatly improved from 125 ± 5 MPa (sand-mold) to 262 ± 3 MPa (SLM) and from 0.8 ± 0.2% (sand-mold) to 4.0 ± 0.2% (SLM), respectively. The strengthening mechanism is discussed, which is mainly ascribed to the continuous refinement of grains and Si particles and an increase in super-saturation of Al matrix with increasing cooling rate.

tooth defects or deletions. Tantalum (Ta) has been widely used in the biomedical field, but its application in artificial dental implants is rarely reported. In this study, Tantalum-Niobium alloy (TaNb40) implant prepared by 3D printing—SLS was used as the research subject. Its mechanical properties in vitro and the biocompatibility by utilizing human Oral Mucosa Fibroblasts (hOMF) were studied. Results: The mechanical property test results were that the Tensile Strength, Yield Strength, Elongation, and Vickers hardness of TaNb40 implant was 548 ± 50MPa, 420 ± 30MPa, 40%, and 425HV, respectively, manifesting the two indicators met the requirements of dental metal implant, and had good mechanical properties of wear resistance and not easy to brittle fracture. The cytocompatibility test showed that TaNb40 did not inhibit cell proliferation and produce cell cycle arrest. The cytotoxicity grade was 1, there was almost no metal ion release in the culture medium, and the surface had fine cell early adhesion, which met the requirements of biomedical materials. Conclusion: The TaNb40 prepared by domestic 3D printing—SLS has excellent mechanical properties and cytocompatibility in vitro, which is expected to replace the Titanium metal implant prepared by the traditional casting method, having a leading significance for the formation of implants with independent intellectual property rights.