Microstructure has significant effects on the mechanical properties of AlSi10Mg alloy. Therefore, an in-depth understanding of microstructure evolution, such as dendrite and Al-Si eutectic, is of great significance to obtain the desirable microstructure and manage the performance of AlSi10Mg components. In the current work, an integrated dendrite and eutectic evolution model based on the cellular automaton–finite difference (CA-FD) method, taking account of solute distribution, growth kinetics, and nucleation mechanism, was established. Microstructures of the as-built selective laser melted (SLMed) samples were characterized by optical microscopy (OM), scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) techniques, and the experimental results showed that the microstructure consisted of Al grains and Al-Si eutectic networks in the individual melt pool. Dendrite growth, solute redistribution in ternary alloy and dendritic morphologies with different cooling rates were numerically investigated. In addition, the proposed model was also applied to predict the Al-Si eutectic evolution, and eutectic morphologies under eutectic undercooling in a range of 5 K to 20 K were also simulated. The simulated results indicated that dendrites were refined with the increasing of the cooling rates, and Al-Si eutectic morphology was sensitive to eutectic undercooling such that higher eutectic undercooling refined the eutectic microstructures. Model validations were performed, and the experimental results agreed well with the simulation results, indicating that the proposed model can successfully reproduce both dendrite and eutectic microstructures.

The effect of the hot oscillatory pressing (HOPing) temperature on the microstructure and tensile behavior of the powder metallurgy superalloys was investigated and compared with those of the hot pressed (HPed) sample. The results show that as the HOPing temperature rises, the pores and residual dendrites disappear, the grain size becomes coarser and more uniform, the prior particle boundaries (PPBs) scale decreases; the yield strength decreases gradually; the ultimate tensile strength and elongation increase first and then decrease; the tensile property stability gradually increases. The highest ultimate tensile strength and elongation of 1403 MPa and 35%, respectively, are reached when the HOPing temperature is 1160 °C. The fracture mode of the sample hot oscillatory pressed (HOPed) at 1160 °C is a transgranular and intergranular mixed fracture. Compared with the HPed sample, room temperature tensile properties of the HOPed sample improve remarkably due to the reduced size and density of PPBs precipitates.