δ Phase precipitation in Inconel 718 and associated mechanical properties
δ Phase precipitation in Inconel 718 and associated mechanical properties
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DOI：
10.1016/j.msea.2016.09.114
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发表时间：
2017-01-02
期刊：
影响因子：
6.4
通讯作者：
Savoie, J.
中科院分区：
文献类型：
--
作者：
Anderson, M.;Thielin, A. -L.;Savoie, J.
研究了Inconel 718合金中8相析出的显微组织及其力学性能。进行了几次热处理，使δ相以各种比例和形态沉淀。热处理在875 ° C至975 ° C的温度范围内进行，持续时间为0.5至24小时。对于每个测试，表征微观结构并量化8种沉淀物的体积分数。平行地，进行单轴拉伸试验以确定合金的机械性能，即颈缩伸长率（N %）、屈服强度（YS）、维氏硬度（HV）和应变硬化系数（K，n）。结果表明，当γ "和δ析出相共存时，材料保持硬化，而与δ相的量无关。当基体中只存在δ相时，其体积分数对材料的成形性没有显著影响。据观察，晶内和晶间析出物之间的比例可以是一个关键参数。当晶间沉淀物的量足够时，会导致材料更好的成形性。相反，当晶内析出物最大化时，它们倾向于硬化材料。最后建议在975 ℃下固溶处理2 h作为改善IN718成形性的最佳折衷方案。
Microstructures generated by 8 phase precipitation in Inconel 718 (IN718) and related mechanical properties were investigated in this paper. Several heat treatments enabling the precipitation of the 5 phase in various proportions and morphologies were conducted. Heat treatments were performed in a temperature range between 875 degrees C and 975 degrees C with time durations from 0.5 to 24 h. For each test, the microstructures were characterized and the volume fraction of the 8 precipitates quantified. In parallel, uniaxial tensile tests were conducted in order to determine the mechanical properties of the alloy, namely the elongation at necking (N%), the yield strength (YS), the Vickers hardness (HV) and strain hardening coefficients (K, n). The results revealed that when gamma '' and 5 precipitates coexist, the material remains hardened regardless of the amount of 5 phase. However, when only delta phase were presented in the matrix, its volume fraction did not significantly affect the formability of the material. It was observed that the ratio between intragranular and intergranular precipitates could be a critical parameter. Intergranular precipitates, when in sufficient amount, led to a better formability of the material. On the contrary, when the intragranular precipitates were maximized, they tend to harden the material. A solution treatment at 975 degrees C for 2 h was finally suggested as the best compromise to improve the formability of IN718.