PSI - Issue 60

Md Rakim et al. / Procedia Structural Integrity 60 (2024) 136–148 Md Rakim et al. / Structural Integrity Procedia 00 (2023) 000 – 000

144

9

9

As-received 1000 hours 5000 hours 20000 hours

9

27 ºC 650 ºC 710 ºC 750 ºC

8

8

6 D KTH ( MPam 0.5 ) 7

0.5 )

7

6 D K TH (MPam

5

5

4

4

0

5000

10000

15000

20000

0

200

400

600

800

Ageing Time (hours) Fig.6: Variation of with ageing time at different temperatures for base material.

Temperature (ºC) Fig.7: Variation of with the temperature at different aged durations for base material.

12

12

27 ºC 650 ºC 710 ºC 750 ºC

0 hours 1000 hours 2000 hours 5000 hours

10

10

6 D KTH ( MPam 0.5 ) 8

6 D KTH ( MPam 0.5 ) 8

4

4

0

200

400

600

800

0

2000

4000

6000

Temperature (ºC) Fig.9: Variation of with temperature at different aged durations for weld material.

Ageing Time (hours) Fig.8: Variation of with ageing time at different temperatures for weld material.

For the base metal, it has been observed that there is a decrease in value within the temperature of 27 °C to high-temperature ranges (650-750 °C) at all aged durations. However, results indicate that there has an unexpected increase in the value of at 20000 hours aged time and at 650 °C temperature conditions. The possible reason behind this observation is the crack blunting phenomenon that delays the crack initiation of the material. Observations suggest that as temperature increases from 650 °C up to 750 °C for 1000 hours and 5000 hours aged durations, there has a considerable decrease in value. The reason behind this happening is that from as received to aged material, there is a decrease in strength that resembles hardness increases in the material, which shows a decrease in value. Another important observation is that there has a small decreasing slope of at 5000 hours to 20000 hours aged condition. The possible reason behind this phenomenon is that the carbide