Instytut Podstawowych Problemów Techniki

Streszczenie:

This study investigates the use of high-frequency eddy current testing (ECT) to assess the structural integrity of aluminide coatings on MAR-M247 nickel superalloy under simulated fatigue conditions. Aluminide coatings, deposited via chemical vapor deposition at thicknesses of 20 µm and 40 µm, were tested using custom-designed probes optimized for defect detection. Results demonstrate that substrate grain structure and coating thickness significantly influence coating durability, with fine-grain substrates exhibiting the least resistance changes and greatest fatigue tolerance. Eddy current signal variations correlated with microstructural changes, enabling detection of damage otherwise invisible to traditional methods. These findings establish ECT as a precise, non-destructive approach for monitoring aluminide coatings in critical applications.

Słowa kluczowe:

Nickel alloys, Aluminide coating, Non-destructive testing, Eddy current testing

Afiliacje autorów:

Streszczenie:

This study investigates the use of eddy current testing (ECT) as a non-destructive technique to evaluate the thickness and structural variations of non-magnetic aluminide coatings on MAR-M247 nickel-based superalloy. Coatings with thicknesses of 20 μm and 40 μm were applied to substrates exhibiting fine, coarse, and columnar grain structures. Using sensors of different geometries, impedance measurements were performed within a frequency range of 11.5 MHz to 12.5 MHz. Results demonstrated the designed sensor’s superior sensitivity, with the highest values of absolute resistance difference significantly exceeding the threshold for reliable distinction due to coating thicknesses or grain structures. The study highlights the impact of eddy current penetration depth and edge effects on the measurement accuracy, emphasizing the need for optimized sensor design and frequency selection. Findings confirm the efficacy of ECT in differentiating coatings of varying thicknesses and substrate structures, offering a reliable tool for quality control in high-temperature applications.

Słowa kluczowe:

Aluminide coating, Eddy current testing, Non-destructive testing, Nickel alloys

Afiliacje autorów:

Streszczenie:

In this paper, the effectiveness of the eddy current methodology for crack detection in MAR 247 nickel-based superalloy with aluminide coatings subjected to cyclic loading was investigated. The specimens were subjected to force-controlled fatigue tests under zero mean level, constant stress amplitude from 300 MPa to 600 MPa and a frequency of 20 Hz. During the fatigue, a particular level of damage was introduced into the material leading to the formation of microcracks. Subsequently, a new design of probe with a pot core was developed to limit magnetic flux leakage and directed it towards the surface under examination. The suitability of the new methodology was further confirmed as the specimens containing defects were successfully identified. The changes in probe resistance values registered for damaged specimens ranged approximately from 8 to 14%.

Słowa kluczowe:

Nickel alloys, Aluminide coating, Non-destructive testing, Eddy current testing

Afiliacje autorów: