Page 92 - IJAMD-1-3

International Journal of AI for
Materials and Design
Review of gas turbine blade failures by erosion

characterized by porosities of 12.9 ± 0.5% and 19.5 ± 1.2%, conditions. The study encompassed nine distinct factors
were subjected to rigorous testing in a high-temperature thoroughly examined and linked to their inclusive
erosion tunnel designed to simulate the operational abrasion performance and the root cause failure of turbine
conditions of contemporary GTEs. The experimental trials blades. Kedir et al. determined the minimal solidity
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encompassed a temperature range spanning from 537°C using a mass-volume system, while the matrix hardness
to 980°C, with gas velocities ranging between 122 m/s was assessed through Vicker’s hardness of the matrix-rich
and 305 m/s, and impingement angles spanning 20° – 90°. region. Furthermore, the research emphasizes the necessity
During the testing process, two types of powders were of a systematic understanding of both material properties
utilized, nominal 27 µm white fused alumina and 15 µm and the operational environment. This approach is crucial
A3, commonly known as test dust. The study concluded in the development and assembling of abrasion-resilient
that erosion rates increased in correspondence with gas CMC engine materials and machineries, ultimately
velocities across all three impingement angles, that is, contributing to the improved reliability and strength of
20°, 60°, and 90°. Furthermore, it was established that the CMC hardware. It also highlights the need for rigorous
experimental variations adhered to an empirical relation, testing protocols to validate material performance
emphasizing the importance of the relationship between under realistic operating conditions, ensuring long-term
the erosion rates and the tested parameters. durability and efficiency.
Kedir et al. conducted comprehensive tests on Rajabinezhad et al. examined the primary factor
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various ceramic matrix composites (CMCs), employing contributing to the failure of gas turbine blades composed
different erodent particles at varying velocities ranging of the Nimonic-105 nickel-based superalloy. Their
between 200 m/s to 300 m/s under ambient temperature investigation focused on two specific blades, one fractured
at the root and the other at the airfoil, delving into the
A B intricate details to identify the underlying causes of these
failures. Images displaying the fracture surface of the root-
failed blade, captured using a stereomicroscope and SEM,
are depicted in Figure 5. They meticulously analyzed the
material properties and structural integrity of the blades
to gain a comprehensive understanding of the failure
mechanisms at play. Figure 6 illustrates the fractured
surface of a gas turbine blade, which has become detached
Figure 3. SEM images showing surface damage morphologies of durable, from the aerofoil. The aerofoil is the primary section of
low conductivity thermal barrier coatings during erosion and impact the blade responsible for directing airflow and converting
tests. (A) Limited plasticity erosion surface with small fatigue spalling thermal energy into mechanical power. In this image, the
areas (indicated by arrows). (B) Extensive plasticity impact surface with blade’s root or attachment point to the turbine hub has
widespread spalling. Source: Zhu et al. 59
Abbreviation: SEM: Scanning electron microscopy. failed, which typically indicates a significant mechanical
stress or fatigue fracture. The fracture surface provides
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critical insights into the failure mechanism, including
whether the failure was driven by fatigue, corrosion, or

A

B C

Figure 5. Micrographs of the fractured surface of the root-failed blade.
Figure 4. The correlation between erosion and impact rates was examined (A) Stereomicroscope image. (B and C) SEM micrographs. Source:
for 50 and 560 μm erodent particles in specific coating systems under Rajabinezhad et al. 76
testing at 2200 F (1204°C). Source: Zhu et al. 59 Abbreviation: SEM: Scanning electron microscopy.

Volume 1 Issue 3 (2024) 86 doi: 10.36922/ijamd.5188