Thermal ageing and short-range ordering of Alloy 690 between 350 and 550 °C

Modeling and Simulation of Microstructure Evolution and Deformation in an Irradiated Environment

“…With this trend in mind, we recognize that similar plastic regime force response between the [100] simulation result and the [213] experimental data indicates an underprediction of the micropillar response by our crystal plasticity framework. Similarly, although the simulation results for the [111] oriented micropillar exceed the experimental data, previous experimental measurements in different loading orientations have determined that the stress response for loading in the [111] direction significantly exceeds the [123] response for FCC materials [178,67]. The underprediction of the micropillar force response by our crystal plasticity simulations is apparent in the thermally aged comparison, Figure 5.5b.…”

“…We note that bulk single crystal experiments indicate that the stress response for loading in the [100] and [111] directions should be higher than the stress response from the [123] loading direction [178,67,10]. The higher stress response is a consequence of the multiple slip systems which are active in the [100] and [111] loading directions compared to the only two active slip systems in the [123] type loading orientation. Since the stress response is calculated from the force response, we expect the same trends to hold as we compare the force-displacement curves.…”

“…The use of nickel alloys for piping materials in chemical industry processing plants over decades provides a set of information on the in operation aging of commercial nickel alloys. Several studies have analysized the microstructure of nickel-based alloys after 50,000 hrs to 70,000 hrs of in service operation at temperatures of 450 o C to 600 o C [184,175,164,193,123]. Among the several precipitates and particles which form in these complex alloys is the formation of long ranged ordered (LRO) Ni 2 Cr precipitates [112].…”

Effects of Aging Time on Microstructure and Oxidation Behavior of Inconel 690 Alloy

“…Meanwhile, Mouginot et al [11] also found that the Cr-rich M 23 C 6 increased with increasing aging temperature in all conditions. Therefore, heat treatment has a signi cant effect on the structural stability.…”

“…This is because the presence of Cr-rich carbides in Inconel 690 alloy can hinder the initiation and propagation of cracks in the corrosion process, and intergranular cracks promote crack tip blunting and increase the resistance to cracking [6,7]. In order to further analyze Cr-rich carbides, a large number of studies have been carried out [8][9][10][11]. Lee et al [8] found that the Cr-rich M 23 C 6 generated on the grain boundaries in an aging temperature range of 650-925°C, while no precipitates were observed under 600°C or over 925°C.…”