Integrated control of molten pool morphology and solidification texture by adjusting pulse duration in laser additive manufacturing of Inconel 718

Abstract

Both single-track and bulk Inconel 718 samples were fabricated using pulsed laser additive manufacturing to investigate the effect of pulse duration on the molten pool morphology and the solidification texture. For single-track depositions, clad width, remelting depth, dilution ratio and peak molten pool temperature decrease, while clad height, clad area, minimum temperature and molten pool lifetime increase with the increase of the pulse duration. The fusion line of the molten pool in transverse direction is pan-like at a short pulse duration (20 ms), and gradually turns circular (60 ms) as the pulse duration increases. For bulk samples, uniform grains with a strong fiber texture are established for a short pulse duration. In contrast, alternatively distributed coarse grains in the overlapping region and fine grains at the center of the molten pool with a weak cube texture are obtained for a long pulse duration. In addition, samples fabricated with short pulse durations contain less volume fraction of Laves phase than that with long pulse durations. Pulsed laser additive manufacturing has the potential for texture control and in-situ production of components with functional graded textures.