| Abstract Scope |
Microstructure evolution, tensile and high cycle fatigue properties of AlSi10Mg alloys manufactured by selective laser melting were investigated according to two different post heat-treatments. Direct aging (D.A.) and T6 heat treatments were conducted respectively for SLM AlSi10Mg alloys. Regardless of post heat-treatments, AlSi10Mg alloys consisted of α-Al, eutectic Si, AlFeSi intermetallics, and nano-sized precipitates (Mg<sub>2</sub>Si). Microstructure characteristics such as molten pool, cellular-structure, and precipitates were analyzed quantitatively by OM, FE-SEM, EBSD, and TEM. Yield strengths of as-bulilt, direct-aged, and T6 heat treated alloys were 264MPa, 310MPa and 180MPa, respectively. Tensile strengths of as-built and direct-aged alloys were similar, but higher than that of T6 heat treated alloy. High cycle fatigue results showed that the direct-aged alloy had significaltly higher fatigue property compared to those of as-built and T6 alloys. Fracture surfaces and deformed microstructures were analyzed and the strengthening and fracture mechanisms of SLM built AlSi10Mg alloys were also discussed. |