계량원소 첨가, 열처리 및 표면처리 공정을 활용한 LPBF-built AlSi10Mg 합금의 미세조직 및 인장 기계적특성 향상

초록

For the past decade, prominent evolution regarding laser powder bed fusion (LPBF) processing was established regarding process productivity, reliability, and quality. Many researchers were focused to modify Al alloys for an LPBF process to achieve better material performance these days. In this investigation, influence of heat treatment, modifier and surface treatment on the microstructure and tensile properties of AlSi10Mg alloy manufactured by the LPBF process. Efforts to improve better material strength and properties; at first method, as-built AlSi10Mg alloy were heat treated under two different conditions, namely T6 and direct aging (DA). Then, predominant attempted to added 150 ppm Strontium (Sr) as a modifier to the as-built AlSi10Mg alloy. Finally, the dragging surface treatment was carried out to achieve outstanding mechanical properties. Microstructural variation, mechanical and tensile properties of these three different methods were compared and evidently reported in this investigation. Primarily, the tensile property was influenced by morphology and size of Si particles which are controlled by heat treatment methods. DA heat-treated alloy showed a better tensile strength of 447.9 MPa due to the cellular structural morphology with presence of significant amount of fine Si precipitates on it. The modified AlSi10MgSr alloy exhibits a better ultimate tensile strength of 456.3 MPa, which is attributed to the significant grain refinement of ???Al grains and Al-Si eutectic cells. Among these, the maximum tensile strength and elongation of 487.24 MPa and 11.69 % were achieved by the dragging surface treatment condition, respectively. Surface treatment can effectively transfer tensile to compressive residual stress on surface which can enhance the strength of the material and reduction in surface roughness on surface can suppress the stress concentration, crack propagation and also encloses the surface connected pores that makes it as an internal fracture, so