MOHAMMAD FAHIM

High Temperature Characterisation of INCONEL 740H The study focuses on evaluating the microstructural properties and high temperature behavior of INCONEL 740H, a nickel-based superalloy. Samples are aged at 750°C and 800°C for different durations to investigate the effects of aging time and temperature. Microstructural analysis reveals the presence of various precipitates such as carbides, borides, and γ'- Ni3(Al, Ti) intermetallic, which contribute to the alloy's excellent high temperature performance. Optical microscope and SEM images are used to observe the changes in the microstructure with varying aging time and temperature. Hardness tests are conducted to assess the hardness of the samples. The results show that the hardness increases with aging time at 750°C, while there is a decrease in hardness with increasing aging time at 800°C. This suggests that the alloy's wear resistance may be compromised at higher aging temperatures. To assess the effect of fly ash on the fire side of Inconel 740H components in AUSC applications, a hot air test is performed. The test is conducted at 750°C and 800°C, and the impact angle of the fly ash particles is varied. Contrary to expectations, there is an increase in weight of the sample after the test, indicating that fly ash particles diffuse into the material. The weight gain is higher at the normal impact angle compared to the impact angle of 60°. Moreover, as the test duration increases, the weight gain decreases, indicating a decrease in the rate of diffusion of coal ash into the sample over time. This finding opens up opportunities for studying changes in the heat transfer rate in boiler parts after prolonged use. Overall, the study provides insights into the microstructural properties, hardness, and erosion behavior of INCONEL 740H under high temperature conditions. These findings contribute to understanding the material's suitability for advanced power generation systems and highlight areas for further research and optimization.

Additive Manufacturing