Effect of Cr and Re on the Oxidation Resistance of Ni₃Al-Base Single Crystal Alloy IC21 at 1100

Abstract

The oxidation kinetic curves of three Ni3Al-based single crystal alloys (IC21, IC21C and IC21CR) with different Cr and Re content were examined at 1100. The microstructures and element distributions of the oxide scales on these alloys were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive X-ray spectrometry (EDS). Results revealed that the oxidation resistance of these alloys was improved in the order of IC21 < IC21C < IC21CR. The oxide products of IC21 mainly consisted of NiO, α-Al2O3, NiAl2O4and a small amount of NiMoO4and MoO2. The volatilization of Mo oxides led to the oxide scale spallation from IC21C, thus deteriorated the oxidation properties. While for IC21C and IC21CR, the oxidation resistance was significantly improved. The Mo oxides in the oxide layer were greatly reduced and a continuous α-Al2O3layer was formed.

Isothermal Sections of the Ni-Cr-Ta Ternary System at 1200 °C and 1300 °C

“…However, with higher industrial requirements in the structure materials for high-temperature applications in aviation field, materials capable of better mechanical strength, oxidation and corrosion resistance are required. In order to improve the properties of Ni-based alloys, an excellent alternative is to alloy refractory elements [3][4][5][6]. Technologically, Cr addition could significantly improve the oxidation and hot-corrosion resistance for the nickel-based alloys by forming a stable oxidation protective layer Cr 2 O 3 at elevated temperatures [4,[7][8][9].…”

“…In order to improve the properties of Ni-based alloys, an excellent alternative is to alloy refractory elements [3][4][5][6]. Technologically, Cr addition could significantly improve the oxidation and hot-corrosion resistance for the nickel-based alloys by forming a stable oxidation protective layer Cr 2 O 3 at elevated temperatures [4,[7][8][9]. Meanwhile, as a solid solution strengthening element, the alloying of Ta also improves the hot-corrosion and oxidation resistance [10,11].…”

Oxidation and microstructure evolution of Al–Si coated Ni3Al based single crystal superalloy with high Mo content

“…This superalloy exhibits excellent high temperature mechanical properties. However, the high Mo content (8∼10 at.%) within the superalloy results in a poor oxidation resistance, due to the formation of volatile Mo oxides [16]. To address this problem, IC211 superalloy with reduced Mo content (5∼8 at.%) was further developed.…”

Effects of Re on Microstructure of Ni₃Al-Based Single Crystal Superalloys

“…Recently, the research on the Ni 3 Al-based single crystal superalloys, characterized by Re addition, has been more attractive. Re addition has been reported to influence the recrystalization behavior [14] and increase the oxidition resistance [15] of Ni 3 Al-based single crystal superalloys. However, there are limited systemetic investigations regarding the effects of Re addition on the solidus/liquidus temperatures, solidification segragation, microstructure and long-term microstructural stability of Ni 3 Al-based single crystal superalloys.…”