A post-creep deformation analysis is carried out on the nickel-based superalloy Inconel 617 in order to identify the grain boundary carbide (GBC) distributions for different creep stresses and temperatures and to determine the related microstructural changes in terms of grain size and associated changes in the material’s creep ductility as a function of GBC distribution. Creep tests were conducted at two temperatures 900 °C and 950 °C for stresses of 35, 50, and 62 MPa. Post-creep rupture, carbide size, density, and spacing were measured as a function of grain boundary orientation with respect to the loading direction (i.e., trace angle). It is observed that non-uniform carbide distributions were present in the five test conditions associated with an increase in the carbide size, density, and area fraction along grain boundaries perpendicular to loading conditions (tensile boundaries) when compared to those on parallel boundaries (compressive boundaries). The magnitude of preferential distribution of GBC towards tensile boundaries is observed to govern the ability of the compressive boundaries to migrate which facilitates grain elongation in the loading direction which leads to increased creep ductility. A critical magnitude of preferential GBC distribution is determined below which compressive boundaries remain relatively pinned with a low grain boundary spacing. This condition corresponds to creep deformation accommodated by grain boundary sliding only, leading to a relatively low creep rupture strain. Above that magnitude, compressive boundaries are permitted to slide and migrate and, as such, facilitate grain elongation giving rise to increasing magnitude of total creep strain. A criterion for significant preferential distribution, or preferential distribution resulting in changes to grain morphology and mechanical response, has been proposed in the form of a temperature-stress map which identifies the creep loading conditions associated with significant preferential distribution prior to creep rupture. The critical GBC distribution coupled with the concept of identifying temperature and stress combinations resulting in significant preferential distribution provides guidelines for creep testing for the purpose of extrapolating short-term test data to long-term behavior.

对镍基超合金Inconel 617进行蠕变后变形分析，以识别不同蠕变应力和温度下的晶界碳化物（GBC）分布，并确定晶粒尺寸和相关变化方面的相关微结构变化材料的蠕变延展性取决于GBC分布。在35、50和62 MPa的应力下，分别在900°C和950°C的两个温度下进行了蠕变测试。蠕变后的破裂，碳化物的大小，密度和间距是相对于加载方向（即，即，走线角）。观察到，与平行边界（压缩）相比，在五个测试条件下存在不均匀的碳化物分布，这与沿垂直于加载条件（拉伸边界）的晶界的碳化物尺寸，密度和面积分数的增加有关。边界）。观察到GBC朝向拉伸边界的优先分布的大小决定了压缩边界迁移的能力，这有利于晶粒在加载方向上的伸长，从而导致蠕变延展性的提高。确定优先GBC分布的临界大小，在该大小以下，压缩边界保持相对固定，且晶界间距较小。此条件仅对应于晶界滑动所适应的蠕变变形，导致较低的蠕变断裂应变。超过该大小，允许压缩边界滑动和迁移，因此，有利于晶粒伸长，从而导致总蠕变应变的大小增加。已经以温度-应力图的形式提出了显着的优先分布或导致晶粒形态和机械响应变化的优先分布的准则，该温度-应力图确定了蠕变破裂之前与显着的优先分布相关的蠕变载荷条件。关键的GBC分布与识别温度和应力组合的概念（导致显着的优先分布）结合在一起，为蠕变测试提供了指导原则，目的是将短期测试数据推算为长期行为。