Microstructure evolution of a new directionally solidified Ni-based superalloy after long-term aging at 950 °C upto 1 000 h

Lifetime extension prediction of the rejuvenated first stage gas turbine blades

“…In addition to these nucleated precipitates, several cavities were generated in the aged blades heterogeneous microstructure after 55,000 EOH at 870°C mixed with aligned γ′ phase as shown in Figure 5(b), provide evidence of the entrance in tertiary creep phase that can provoke buckets failure. Another life-limiting phenomenon mainly observed in aged buckets nickel-based superalloys at 870°C, was the transformation exhibited in Figure 6, of large blocky MC-Carbides rich in (Ti, Ta) found in γ-matrix into coarse brittle Cr rich M 23 C 6 lines network at the grain boundaries of GTD-111 base material [19,20]. On another side, the cold air circulated during service inside the buckets internal channels, had reacted directly with blades base metal and formed an accumulated thick layer of (Al 2 O 3 , TiO, C 2 O 3 , Er 2 O 3 , SiO 2 ) mixed oxides scales (as shown in Figure 7).…”

The Bootstrap Analysis of One-Way ANOVA Stability in the Case of the Ceramic Shell Mould of Airfoil Blade Casting

“…The precipitation and growth kinetics of the γ' phase are highly sensitive to the rate at which the alloy is cooled through the solvus temperature. The (γ+γ') eutectic is an indication of the remaining melt at the end of the solidification process [7,8]. After solution heat treatment, the microstructure with (γ+γ') eutectic should be homogenized [9].…”

Medium-temperature calcination and acid pressure leaching extract the Al2O3 from coal gangue: activation mechanism and kinetic analysis

“…The alkali fusion method has the shortcomings of high alkali consumption, complex processing, and a large amount of waste residue, while the acid method of extracting Al 2 O 3 from coal gangue has the advantages of high efficiency and simplicity. Guan et al , 18 extracted Al 2 O 3 directly under a hydrochloric acid system by adding sodium fluoride, and the extraction ratio of Al 2 O 3 only reached only 70.40%. The structures of kaolinite, muscovite, and orthoclase within coal gangue are stable, and hydrochloric acid is not reactive and cannot efficiently extract Al 2 O 3 .…”