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Effect of thermal history on microstructure and mechanical properties of laser direct energy deposited Inconel 718
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J
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J
DOI：10.1016/j.cirpj.2026.02.007.png)
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Abstract
En 中文
To address the challenge of non-equilibrium microstructural control during laser directed energy deposition (LDED) of Inconel 718 superalloy, this study systematically investigated the influence mechanisms of interlayer cooling time on microstructural evolution and mechanical properties. The thermal history under varying interlayer cooling times was systematically investigated through integrated simulation and experimental approaches. Multiscale characterization techniques were employed to elucidate dendrite morphology transformation and grain orientation distribution characteristics, and the quantitative relationship between the cooling rate and the primary dendrite arm spacing was established. The mechanical enhancement mechanism was revealed through room-temperature tensile testing combined with Schmid factor analysis. Experimental results demonstrate that prolonging interlayer dwell time significantly alters thermal history within molten pools, achieving grain refinement and columnar-to-equiaxed transition through coordinated regulation of temperature gradient and solidification rate, while concurrently inducing < 100 > texture weakening. Mechanical testing revealed 12.4 % and 10.8 % strength improvements in scanning direction and building direction respectively when implementing 3-minutes cooling intervals, with fracture surfaces exhibiting dimple-dominated ductile characteristics. Notably, large irregular Laves phases were identified as detrimental to ductility. This research establishes theoretical foundations for in-situ microstructural control in laser additive manufacturing of nickel-based superalloys.
Keywords:
Laser directed energy deposition
Interlayer dwell time
Thermal history
Microstructure
Tensile property
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5.4
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283
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4.8K
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