The elevated temperature tensile properties of SLM IN718 were measured as a function of strain rate and test temperature to better understand the time-dependent and thermal aspects of environmental sensitivity. SLM and wrought materials were solution treated, aged, and tested over the range of 550–750 °C and 10⁻³ to 10⁻⁶ s⁻¹. The SLM material tested across all conditions had inferior strength and ductility compared to wrought material of the same heat treatment because of environmental sensitivity in the form of dynamic embrittlement. SLM samples show evidence of brittle intergranular fracture, crack growth, and oxidized NbC particles on the fracture surface, which all contribute to the observed poor ductility. These features, and subsequent embrittlement, are intensified with decreasing strain rate and increasing temperature. Higher strain rates and lower temperatures are shown to improve the ductility in SLM IN718 but despite this recovery it remains susceptible to environmental attack even in the extreme cases of the current study. The prevalence of NbC at grain boundaries in the SLM material is the principal source of dynamic embrittlement and environmental sensitivity.

SLM IN718 的高温拉伸性能作为应变速率和测试温度的函数进行测量，以更好地了解环境敏感性的时间相关性和热性方面。SLM 和锻造材料在 550-750 °C 和 10 ^-3到 10 ^-6 s ^-1的范围内进行固溶处理、时效和测试. 由于动态脆化形式的环境敏感性，与相同热处理的锻造材料相比，在所有条件下测试的 SLM 材料具有较差的强度和延展性。SLM 样品显示出脆性晶间断裂、裂纹扩展和断裂表面上氧化的 NbC 颗粒的证据，这些都是观察到的较差延展性的原因。这些特征以及随后的脆化随着应变速率的降低和温度的升高而加剧。更高的应变率和更低的温度被证明可以提高 SLM IN718 的延展性，但尽管有这种恢复，即使在当前研究的极端情况下，它仍然容易受到环境攻击。