Compositional effects on the cyclic oxidation resistance of conventional superalloys

Abstract

The 1100 °C cyclic oxidation performance of 25 Ni-base commercial and developmental alloys was compiled from an extensive database and ranked according to the 200 h weight change. Cyclic oxidation performance of superalloys is directly controlled by composition. These conventionally cast superalloys were composed of base elements [Ni-Co-Cr-Al], refractory elements [Nb-Mo-Ta-W], oxygen-active elements [Ti-Zr-Hf], light elements [B,C], and occasionally [V-Mn-Si], with P and S trace impurities. The oxidation results were broadly categorised as less than 4 mg/cm 2 weight loss for alloys with high 5-6% Al and 3-9% Ta, and with low ≤ 1% Ti (wt.%). Conversely, weight loss of 200-300 mg/ cm 2 characterised alloys containing low < 3.5% Al, no Ta, and high > 3% Ti. These trends correlated with beneficial and detrimental scale phases previously reported. An unambiguous Cr effect was masked because of its strongly coupled, but inverse, correlation with Al. Multiple linear regression was used to fit alloy composition to a simple logarithmic weight change transform. The function contained 10 terms and yielded a correlation coefficient, r 2 , of 0.84. Various graphical representations helped to further illustrate, quantify, and predict complex oxidation effects within a 10-element compositional space.

Comparison of the effect of EB and LB surface treatment on structural characteristics of IN 713LC superalloy

“…Three types of possible preferential oxide layers could be expected for Ni-Cr-Al systems [9] oxides can be assumed according to EDS results. In literature, the presence of Cr 2 O 3 and NiCr 2 O 4 or also NiO is mainly discussed [31]. However, some studies also mentioned the presence of TiO 2 in the external oxide layer [31][32][33].…”

Isothermal short‐term oxidation behavior of MAR‐M246 nickel‐based superalloy at 800°C and 1000°C

“…Smialek and Bonacuse [ 13 ] studied 25 commercial superalloys subjected to cyclic oxidation tests at 1100°C for 200 cycles of 1 h. In these test conditions, MAR‐M246 superalloy showed a variation in mass per unit area equal to −24.44 mg/cm 2 , ranking 11th (in decreasing order) among the 25 studied alloys. For comparison, MAR‐M247 was the 6th losing just −4.22 mg/cm 2, and MAR‐200(Hf) was the 17th with −89.8 mg/cm 2 .…”

“…It was found that most of the studies reported in the literature involved cyclic oxidation tests. However, according to Smialek and Bonacuse, [ 13 ] both isothermal and cyclic oxidation tests are essential to obtain a complete description of the degradation of nickel‐based superalloys at high temperatures and in oxidizing atmospheres. Thus, given the importance of studying the behavior of superalloys in isothermal conditions and the paucity of works in the literature in these situations, this study aimed to evaluate the oxidation resistance of MAR‐M246 superalloy at high temperatures under isothermal conditions and to perform a microstructural characterization (SEM‐EDS and X‐ray diffraction [XRD]) of oxides under different conditions of time and temperature.…”

Avaliação do comportamento mecânico em fluência e de oxidação da superliga MAR-M246 convencional e modificada pela substituição do Ta pelo Nb

“…Além disso, de acordo com as previsões desses autores, a superliga MAR-M246 atende o índice Al + 1/2Cr = 10 e portanto deve apresentar boa resistência à oxidação como uma liga à base de Ni-Cr-Al (SMIALEK;G.H.MEIER, 1987). Em geral, o comportamento de oxidação observado para MAR-M246 modificado está de acordo com as previsões empíricas realizadas por Smialek , Bonacuse, Sims e Stolloff (SMIALEK;G.H.MEIER, 1987;BONACUSE, 2016).…”

“…A boa resistência em geral à oxidação das duas ligas investigadas neste trabalho está principalmente relacionada à formação de óxidos protetores como Cr2O3 e Al2O3 (SMIALEK; BONACUSE, 2016) . A formação desses óxidos está diretamente influenciada pela quantidade de Cr e Al presente na liga, bem como pela contribuição dos outros elementos de liga.…”