The microstructures induced by the laser-powder bed fusion (L-PBF) process have been widely investigated over the last decade, especially on austenitic stainless steels (AISI 316L) and nickel-based superalloys (Inconel 718, Inconel 625). However, the conditions required to initiate recrystallization of L-PBF samples at high temperatures require further investigation, especially regarding the physical origins of substructures (dislocation densities) induced by the L-PBF process. Indeed, the recrystallization widely depends on the specimen substructure, and in the case of the L-PBF process, the substructure is obtained during rapid solidification. In this paper, a comparison is presented between Inconel 625 specimens obtained with different laser-powder bed fusion (L-PBF) conditions. The effects of the energy density (VED) values on as-built and heat-under microstructures are also investigated. It is first shown that L-PBF specimens created with high-energy conditions recrystallize earlier due to a larger density of geometrically necessary dislocations. Moreover, it is shown that lower energy densities offers better tensile properties for as-built specimens. However, an appropriate heat treatment makes it possible to homogenize the tensile properties.

中文翻译：

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激光粉末床熔合（L-PBF）获得的Inconel 625合金的铸态组织和再结晶现象的分析

在过去的十年中，激光粉末床熔合（L-PBF）工艺引起的微观结构得到了广泛的研究，特别是在奥氏体不锈钢（AISI 316L）和镍基高温合金（Inconel 718，Inconel 625）上。但是，在高温下引发L-PBF样品重结晶所需的条件需要进一步研究，尤其是关于L-PBF过程引起的子结构的物理起源（位错密度）。实际上，再结晶在很大程度上取决于样品的子结构，在L-PBF工艺的情况下，该子结构是在快速凝固过程中获得的。在本文中，比较了使用不同激光粉末床熔合（L-PBF）条件获得的Inconel 625标本。能量密度的影响（VED）还研究了在建和在热条件下的微观结构的值。首先表明，由于几何必要位错的密度较大，在高能条件下产生的L-PBF标本会较早地重结晶。此外，结果表明，较低的能量密度可为标本提供更好的拉伸性能。但是，适当的热处理可以使拉伸性能均匀化。