Inconel^®718 is a well-known nickel-based super-alloy used for high-temperature applications after thermomechanical processes followed by heat treatments. This work describes the evolution of the microstructure and the stresses during hot deformation of a prototype alloy named IN718WP produced by powder metallurgy with similar chemical composition to the matrix of Inconel^®718. Compression tests were performed by the thermomechanical simulator Gleeble^®3800 in a temperature range from 900 to 1025 °C, and strain rates scaled from 0.001 to 10 s⁻¹. Flow curves of IN718WP showed similar features to those of Inconel^®718. The relative stress softening of the IN718WP was comparable to standard alloy Inconel^®718 for the highest strain rates. Large stress softening at low strain rates may be related to two phenomena: the fast recrystallization rate, and the coarsening of micropores driven by diffusion. Dynamic recrystallization grade and grain size were quantified using metallography. The recrystallization grade increased as the strain rate decreased, although showed less dependency on the temperature. Dynamic recrystallization occurred after the formation of deformation bands at strain rates above 0.1 s⁻¹ and after the formation of subgrains when deforming at low strain rates. Recrystallized grains had a large number of sigma 3 boundaries, and their percentage increased with strain rate and temperature. The calculated apparent activation energy and strain rate exponent value were similar to those found for Inconel^®718 when deforming above the solvus temperature.

中文翻译：

---

镍基高温合金的热变形行为

铬镍铁合金^® 718是用于热机械处理，接着通过热处理后的高温应用公知的镍基超合金。这项工作描述了微结构的演变和命名IN718WP原型合金的热变形时的应力产生的粉末冶金用类似的化学成分，以因科镍合金的基体^® 718压缩试验通过进行热机械模拟器GLEEBLE ^® 3800中的温度范围从900到1025°C，应变速率从0.001到10 s ^-1缩放。IN718WP的流动曲线显示类似的特征的那些因科镍合金的^® 718的相对应力软化IN718WP物与标准合金因康镍合金^® 718为最高应变率。在低应变速率下的大应力软化可能与两种现象有关：快速的再结晶速率和由扩散驱动的微孔的粗化。动态重结晶等级和晶粒尺寸使用金相学定量。随应变率的降低，重结晶度增加，尽管对温度的依赖性较小。在形变带形成后，以0.1 s ^-1以上的应变速率发生动态再结晶以及在低应变率下变形时的亚晶粒形成之后。重结晶晶粒具有大量的sigma 3边界，并且它们的百分比随应变速率和温度的增加而增加。所计算出的表观活化能和应变率的指数值的那些相似找到的因科镍合金^®上面的固溶线温度时变形718。