Knowledge of process-structure-property relationships to engineer better heat treatments for laser powder bed fusion additive manufactured Inconel 718
Knowledge of process-structure-property relationships to engineer better heat treatments for laser powder bed fusion additive manufactured Inconel 718
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DOI：
10.1016/j.addma.2019.100977
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发表时间：
2020-01-01
影响因子：
11
通讯作者：
Stebner, Aaron P.
中科院分区：
文献类型：
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作者：
Gallmeyer, Thomas G.;Moorthy, Senthamilaruvi;Stebner, Aaron P.
在通过激光粉末床熔融增材制造（AM）生产的Inconel 718（IN 718）的微观结构内量化位错结构、化学偏析、γ '、γ“、δ沉淀物和Laves相，并进行标准、直接时效和改进的多步热处理。此外，还记录了仍附着在构造板上的热处理样本与移除的样本的标准热处理。不同的微观结构对室温强度和断裂伸长率的影响。从这些工艺-结构-性能关系得到的知识用于设计AM-IN 718在1020 ℃下超固溶线固溶退火15分钟，然后在720 ℃下时效24小时热处理，其消除了Laves和δ相，保留了显示出由MC碳化物颗粒稳定的AM特定位错胞，并沉淀出致密的γ ′，γ-纳米颗粒群。这种“针对AM-IN 718热处理优化”的结果是相对于锻造/增材制造、然后是行业标准热处理IN 718的上级性能：分别实现了屈服强度7/10%、极限强度2/7%和断裂伸长率23/57%的相对增加，而与印刷表面光洁度和机加工表面光洁度无关。
Dislocation structures, chemical segregation, gamma', gamma '', delta precipitates, and Laves phase were quantified within the microstructures of Inconel 718 (IN718) produced by laser powder bed fusion additive manufacturing (AM) and subjected to standard, direct aging, and modified multi-step heat treatments. Additionally, heat-treated samples still attached to the build plates vs. those removed were also documented for a standard heat treatment. The effects of the different resulting microstructures on room temperature strengths and elongations to failure are revealed. Knowledge derived from these process-structure-property relationships was used to engineer a supersolvus solution anneal at 1020 degrees C for 15 min, followed by aging at 720 degrees C for 24 h heat treatment for AM-IN718 that eliminates Laves and delta phases, preserves AM-specific dislocation cells that are shown to be stabilized by MC carbide particles, and precipitates dense gamma', gamma '' nanoparticle populations. This "optimized for AM-IN718 heat treatment" results in superior properties relative to wrought/additively manufactured, then industry-standard heat treated IN718: relative increases of 7/10 % in yield strength, 2/7 % in ultimate strength, and 23/57 % in elongation to failure are realized, respectively, regardless of as-printed vs. machined surface finishes.