Single Crystal Super Alloy Material Fatigue Behaviour Compared to Ceramic Matrix Composites for Aerospace and Turbine Engine Applications

Dear Colleagues,

Nickel-based single-crystal superalloy materials are generally used for hot turbine engine components such as turbine blades, rotor disks, vanes, and combustor liners. The operating environment is known to be complex and extremely harsh due cyclic high temperatures and high stresses, which lead to fatigue. Besides fatigue loading, these critical engine components are challenged by the occurrence of external and internal surface damage, including corrosion, oxidation, crack formation, erosion, and foreign objects. Combined, these factors accelerate the rate of failure caused by the fatigue loading of such components. Thus, the practical approach to identifying faults in these materials and investigating the cause of malfunctions has been solely based on experimental interpretations and microscopic observations as well as non-destructive evaluation (NDE) inspection. The principal purpose of these methodologies is to investigate fatigue behavior and causes of failure. Analytical modelling to complement the later techniques and to estimate and predict service life has also been proposed and used by many experts in the field. Some of these modelling schemes have limitations since they do not fully consider the anisotropic attributes of the materials and, in the case of the single crystal, the orientation characteristics often are missed. However, much improved life prediction models have recently been developed, where the constitutive behavior of the materials was employed to simulate deformation and allow reliable prediction of fatigue life and of probability of failure.

Ceramic matrix composites (CMCs) are equally being considered for use in aerospace applications. Their characteristics are typically different from those of superalloys. They endure relatively higher temperature environments and they are much lighter. CMCs are one-third the weight of nickel (Ni) superalloys and they can further operate at temperatures up to 260 °C higher. However, analytical modelling of engine components composed of CMCs requires complex test-verified progressive damage models capable of capturing all stages of damage evolution and must consider material processing and manufacturing defects.

Articles and reviews dealing with life prediction of single-crystal superalloy sand CMCs for different market applications, including downstream sponsors, such as manufacturers, vendors, and end users, are welcome. This Special Issue also welcomes studies on various types of superalloys and ceramic matrix composites that are used by end users, such as in aerospace and defense, automotive, energy and power, and electrical, and electronics fields. 

Prof. Dr. Ali Abdul-Aziz
Guest Editor

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• Single-Crystal
• Superalloy
• Turbine Engine
• CMC
• Composites
• Fatigue
• NDE
• Testing
• Durability
• Damage