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The thermal stability of sputter-deposited Mo/Si multilayers was investigated by annealing studies at relatively low temperatures (approximately 250-350 degrees C) for various times (0.5-3000 h). Two distinct stages of thermally activated Mo/Si interlayer growth were found: a primary surge, followed by a (slower) secondary steady-state growth in which the interdiffusion coefficient is constant. The interdiffusion coefficients for the interlayer formed by deposition of Mo-on-Si are higher than those of the interlayer formed by deposition of Si-on-Mo. Assuming that the activation energy is constant, an extrapolation of our results to ambient temperature finds that interlayer growth is negligible, suggesting long-term thermal stability in soft-x-ray projection lithography applications.

This study investigates the effect of post‐heat treatments (solution treatment + aging [SA] and hot isostatic pressing + aging [HIPed]) on the tensile property as well as the room temperature and cryogenic impact toughness of Inconel 718 alloy manufactured by selective laser melting (SLM). The porosities of the three specimens measure SLM SA: 1.10% and SLM HIPed: 0.06%, and wrought SA: 0.01%. Initial microstructural observation shows γ″ + γ′ phase in all three alloys (SLM SA, SLM HIPed, and wrought SA). SLM SA and wrought SA show δ phase of greater fraction compared with SLM HIPed. SLM HIPed and wrought SA show a generally uniform microstructure, and equiaxed grains are found. In tensile tests, SLM HIPed shows greater strength compared with that of wrought SA, but SLM SA shows lowest yield strength among them. The elongations of SLM alloys are ≈1/3 of that of wrought SA. An impact test result shows that impact toughness value at cryogenic temperature of SLM HIPed alloy shows 80% of that of wrought SA. However, SLM SA shows relatively lower impact toughness. In addition, this study attempts to identify the deformation behavior and fracture mechanism of SLM Inconel 718 alloy based on the microstructural characteristics. [ABSTRACT FROM AUTHOR]