PSI - Issue 60

Chinnam Sivateja et al. / Procedia Structural Integrity 60 (2024) 245–255 Sivateja et al. / Structural Integrity Procedia 00 (2023) 000 – 000

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engineering material strength variation), and the CMAS procedure has not affected the static properties (Spear and Ingraffea, 2013). These slight variations are acceptable for replacing the CAA material with the CMAS-AA for structural applications.

Fig. 4. Representative static behaviour of CAA and CMAS-AA specimens

Table 1. Uniaxial Tensile behaviour of Al 2024 T3 alloys (a) CAA and (b) CMAS-AA

0.2 % Yield strength

Ultimate Strength

Young's Modulus

% Elongation

S.No

Condition

MPa

MPa

GPa

%

Mean

313

448

67.3

17.8

CAA- Cladded 2024-T3 sheet specimen, 1.6 mm thickness

1

Std. Dev

11.3

5.7

1.4

1.3

CMAS-AA Chemically milled, anodized, and sealed sheet specimens, 1 mm thick

Mean

348

477

71.0

16.0

2

Std. Dev

4.0

5.0

1.4

1.3

5.3. Residual stress measurement The residual stress in aluminium samples was investigated using X-ray tensor analysis performed by the Sin 2 ψ method , and the measurements were taken from the (311) plane diffraction peak in the XRD Pattern. The resultant residual stress is the mean value of plane stress σ xx and σ yy on the specimen's surface along the specimen's longitudinal and transverse direction. The results revealed distinct differences between the specimens of CAA and CMAS-AA. Specifically, the CAA specimens exhibited a compressive residual stress state of 22.2 (±3.3) MPa, which can be attributed to the compressive rolling forces involved in the cladding process, shown in Fig. 2(a). These compressive forces tend to be retained within the CAA specimens and are beneficial in increasing fatigue life. On the other hand, the CMAS-AA specimens displayed a tensile nature of residual stress, measuring 15.1 (±3.1) MPa. This outcome can be explained by the CMAS procedure, which involves removing the cladded layer with compressive