Hardness variation in inconel 718 produced by laser directed energy deposition
Hardness variation in inconel 718 produced by laser directed energy deposition
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DOI：
10.1016/j.mtla.2022.101643
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发表时间：
2022-12-01
期刊：
影响因子：
3.4
通讯作者：
Todd, Iain
中科院分区：
文献类型：
--
作者：
Chechik, Lova;Christofidou, Katerina A.;Todd, Iain
Inconel 718的定向能量沉积（DED）对于航空航天部件的修复至关重要，这些部件具有严格的认证公差，特别是机械性能。在DED制造的Inconel 718组件中发现了显著的硬度变化，这表明机械性能存在变化，必须了解这些变化，以便根据监管指南在设计中消除或实施这些变化。在这项工作中，尽管Inconel 718通常被认为是γ”强化合金，但γ“沉淀理论上是整个部件硬度变化的原因。一个简单的沉淀电位模型的基础上移动的热源被发现与测得的硬度和解释观察到的硬度分布。此外，已经表明，临界厚度为2 mm以下的截面在竣工条件下永远不会达到峰值硬度。这种理解允许开发原位热处理策略，以开发微观结构，因此，机械性能优化，必要的修复技术，其中后处理步骤是有限的。
Directed energy deposition (DED) of Inconel 718 is of critical importance for the repair of aerospace components, which have tight tolerances for certification, particularly on mechanical properties. Significant hardness varia-tion has been seen throughout DED manufactured Inconel 718 components, suggestive of variation in mechanical properties, which must be understood such that the variation can either be removed, or implemented within the design in line with regulatory guidance. In this work, gamma' precipitation was theorised to be the cause of hardness variation throughout the component, despite Inconel 718 conventionally being regarded as a gamma" strengthened alloy. A simple precipitation potential model based on a moving heat source was found to correlate with the measured hardness and explain the hardness distribution observed. In addition, it has been shown that sections under a critical thickness of 2 mm never reach the peak hardness in the as-built condition. This understanding allows for the development of in-situ heat treatment strategies to be developed for microstructural, and hence, mechanical property optimisation, necessary for repair technologies where post processing steps are limited.