Work-Hardening Behavior of the Ni-Fe Based Superalloy IN718

Abstract

Flow behavior of many metals and alloys in the region of uniform plastic strain is normally expressed by the simple power law relationship (r = Ke p n ). However, deviations have been observed from such behavior in several fcc metallic materials with low stacking fault energy. The age-hardenable nickel-iron base superalloy IN718 is also observed not to obey the simple power law relationship either in the solution treated as well as in the different age-hardened conditions. Various flow relationships were used to obtain the best fit for the experimental data, and different relationships were identified for the different heat-treated conditions. Detailed transmission electron microscopy (TEM) examination of the tensile-tested samples, interrupted after different amounts of strain, revealed inhomogeneous deformation by planar slip in all the heattreated conditions. Cold rolling, however, was found effective in eliminating the unusual plastic flow behavior, observed in the as-heat-treated conditions.

Influence of heat treatment on the microstructure and tensile properties of Ni-base superalloy Haynes 282

“…Also included in Table 3 is followed by a linear decrease with stress (stage III). This is consistent with other observations of Ni-base superalloys [31][32][33]. The stage II hardening rate, q II , is very close to the expected athermal hardening rate (q II =M 2 µ/200), and consistent with the rates observed for shearable precipitates (d<80 nm) in X-750 [29].…”

“…11. On the other hand, the decrease (around 30 HV) is greater than typically observed for solution treated precipitation hardened superalloys, such as Waspaloy [31] and Alloy 718 [32], for a factor of two change in grain size. Thus, the The fact that the 996 °C treatment does not result in a noticeable hardness increase, indicates that the volume fraction of intragranular g' is small, in agreement with the SEM observations ( Figure 10(a)).…”

Effects of cold rolling on the precipitation kinetics and the morphology evolution of intermediate phases in Inconel 718 alloy

“…The behavior can be rationalized based on a low velocity of recovery process in this alloy. Due to a low stacking fault energy of Inconel 718, gliding or climbing of the dislocations is difficult and static recovery proceeds so slowly that grains remain deformed regardless of a long-time andhigh-temperature aging[32].…”

Effects of prior cold working on low cycle fatigue behavior of stainless steels, titanium alloy timetal 834 and superalloy IN 718: A review

“…Therefore, the departure from a simple power law relationship may be associated with a change in deformation. Praveen etal [15] have examined workhardening behavior of this alloy in four different heattreament conditions: peak aged (PA); overaged (OA); and extra overaged (OA100) to obtain completely incoherent precipitates. They also studied the work-hardening behavior of the peak-aged material, following prestraining treatment.…”