Microstructural evolution of platinum modified nickel aluminide bond coat during thermal cycling

Study of the Isothermal Oxidation Process and Phase Transformations in B2-(Ni,Pt)Al/RENE-N5 System

“…The difference in the lattice constant between the simulations and experiments is mainly due to the effect of Pt substitutions in the Ni site. These results are in agreement with the work reported by Chen et al [30]. The effect of Cr and Co on the lattice constant are not expected to be determinant on the size of the unit cell because their atomic radiuses are similar to that of Ni, and according to the triple point defect model and site preferences, they do not affect this parameter.…”

“…This increase is due to Pt-additions (12 at. %) and is in agreement with results reported by Chen et al [30]. In general, it is found that the lattice constant decreases as a function of the thermal exposure time and follows similar trends for NO and SFO experiments during the first stages of the oxidation.…”

“…The behavior of S is also affected by the presence of Pt in the alloy due to their difference in ASF with Al, and this affects the ordering and consequently the stability of the crystal structure, as shown before. 30 The lattice constant of the B2-(Ni,Pt)Al phase shows a linear dependence with the Al content during the complete isothermal oxidation process, irrespective of the nature of the oxidation (NO or SFO). This behavior corresponds to substitutional solid solution alloys, where the elements are replaced by others following a model of hard spheres and where Vegard's law can be applied.…”

The displacement of the thermally grown oxide in thermal barrier systems upon temperature cycling

“…At lower temperatures, the bond coat remains elastic: unless it is subject to a martensite transformation, which results in a volumetric strain upon cooling (Fig. 11) [39]. For practical purposes, instability propagation analysis can be confined to a cyclic range between T 2 and the temperature maximum, with DT T max -T 2 , subject to bond coat yield bc strength, (s Y ) min .…”

Evolution of surface morphology of thermo-mechanically cycled NiCoCrAlY bond coats

“…6. The (yield or creep) strength at the highest temperatures, (σ bc Y ) HT , is in general difficult to measure and can be hard to dif ferentiate from each other [24,25]. Thus, we will study the effect of the high temperature strength on the morphological instability by varying the value of the high temperature (time independent) yield strength in the calculations.…”