Precipitation phases in the nickel-based superalloy DZ 125 with YSZ/CoCrAlY thermal barrier coating
Precipitation phases in the nickel-based superalloy DZ 125 with YSZ/CoCrAlY thermal barrier coating
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DOI：
10.1016/j.jallcom.2011.05.102
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发表时间：
2011-08
影响因子：
6.2
通讯作者：
Tianquan Liang;Hongbo Guo;Hui Peng;S. Gong
中科院分区：
文献类型：
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作者：
Tianquan Liang;Hongbo Guo;Hui Peng;S. Gong
研究了CoCrAlY粘结层与定向凝固镍基高温合金DZ 125在热障涂层中的互扩散行为。在1050°C的空气中退火期间，发生Al、Co和Cr从BC向高温合金的严重向内扩散以及Ni和难熔元素如W从高温合金的向外扩散。退火100 h后，BC与高温合金之间形成了厚度约为30μm的互扩散区（IDZ），IDZ下方形成了厚度约为35μm的二次反应区（SRZ）。IDZ主要由β相和γ基体组成。此外，在IDZ中还观察到少量的含Ta和Hf的碳化物。SRZ中含有大量的针状和细颗粒状拓扑密堆积（TCP）相，以菱形μ相为特征。SRZ的形成主要是由于W、Mo等难熔元素从γ基体和β相中析出。讨论了SRZ和μ-TCP相的形成机理。
Interdiffusion behavior of the thermal barrier coating (TBC) with the CoCrAlY bond coat (BC) and directionally solidified Ni-based superalloy DZ 125 was investigated. Severe inward-diffusion of Al, Co and Cr from the BC to the superalloy and outward diffusion of Ni and refractory elements such as W from the superalloy occur during annealing at 1050°C in air. After 100h annealing, a ∼30μm thick inter-diffusion zone (IDZ) forms between the BC and superalloy, and a ∼35μm thick secondary reaction zone (SRZ) forms beneath the IDZ. The IDZ mainly consists of β phase and γ matrix. Besides, small amount of Ta and Hf containing carbides are also observed in the IDZ. Needle and fine granular topologically close-packed (TCP) phases, characterized as rhombohedral μ phases, are abundant in the SRZ. The formation of SRZ is mainly due to the precipitation of refractory elements such as W and Mo from the γ matrix and β phase. The formation mechanism of SRZ and μ-TCP phase is discussed.