K002和K19H合金组织稳定性的研究

 本文对比地研究了两种低铬-高钨系列的铸造镍基高温合金的铸态显微组织,在850～1100℃范围内热暴露1000～3000小时后的相析出规律,显微组织和微量相的变化及铝化物涂层的蜕化。 试验结果表明这些合金具有高的组织稳定性,标准成份的合金在所有热暴露条件下不析出TCP相,经1050℃/1000小时后K002和K19H合金中微量相总量只分别增加了89％和18％。 提出了下列反应:由于上述反应夺取γ中残余的碳,抑制了M_6C和M_(23)C_6的形成。 此外,在K19H的MC碳化物中含有大量Nb使MC稳定,因此减缓了下列反应;

THE INVESTIGATION ON THE MICROSTRUCTURE STABILITY OF CAST NICKEL-BASE SUPERALLOY K002 AND K19H

In this paper the as-cast microstructure, the rules of phase precipitation, the change of microstructure and minor phase content and the degeneration of aluminide coating after thermal exposure at temperature range from 850℃ to 1100℃ for 1000-3000 hours have been studied in comparison between two kinds of low chromium-high tungsten cast nickel-base superalloys.The experimental results have shown that these alloys have high structural stability, the alloys of normal composition did not precipitate TCP phase in all thermal exposure conditions and the total amount of minor phase in K002 and K19H after thermal exposure at 1050℃/1000 hr. only increased by 89%and 18% respectively. The following reactions have been proposed:Because the above reactions pick up residual carbon in γ-matrix, the formation of M6C and M23C6 is restricted.Besides, large quantity of niobium containing in MC carbide of K19H mates MC stabilize, therefore slows down the following reaction