The effects of Ta on the stress rupture properties and microstructural stability of a novel Ni-base superalloy for land-based high temperature applications
The effects of Ta on the stress rupture properties and microstructural stability of a novel Ni-base superalloy for land-based high temperature applications
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Ta对陆基高温应用新型镍基高温合金应力断裂性能和微观结构稳定性的影响
DOI：
10.1016/j.matdes.2014.04.055
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发表时间：
2014-09
影响因子：
8.4
通讯作者：
Li, Zhou
中科院分区：
文献类型：
--
作者：
Gorley, Michael J.;Wang, Yue;Xiao, Chengbo;Li, Zhou
开发了一种新型多晶镍基高温合金，用于等温锻造模具和工业燃气轮机等地面高温应用。该合金在1100℃/118 MPa下具有52 h的高应力断裂寿命，与第一代单晶（SC）高温合金相当，并具有良好的组织稳定性。研究了添加Ta对合金相变、应力断裂性能和显微组织稳定性的影响。结果表明，Ta是γ′-前体，促进共晶γ′的形成。在1100℃/118 MPa时，共晶γ′含量为~ 7 vol.%的合金比共晶γ′含量为~ 20 vol.%的合金具有更高的应力断裂寿命。然而，过量的共晶相（~ 20vol .%）在760°C、686 MPa的中温条件下提高了应力断裂寿命，但削弱了高温应力断裂性能。（Al + Ta）含量大于14.4 at。%导致了大量共晶γ′的形成，并超过了W和Mo在残液池中的溶解度，促进了初生α-(W,Mo)和M6C相的析出。钽也是一种强碳化物形成元素。形成单碳化物的能力由NbC→TaC→TiC依次递减。6Al-0Ta （wt.%）合金具有良好的组织稳定性，850℃/3000 h、900℃/1000 h热暴露后均未观察到有害的拓扑紧密堆积（TCP）相。在1100℃/ 100-500 h热暴露时，无Ta和5Al-4Ta （wt.%）合金中仅出现微量的二次片状M6C碳化物，但过量的Ta会使合金失稳，在1100℃热暴露后析出大量的二次片状M6C碳化物。透射电镜（TEM）和选择区域电子衍射（SAED）结果表明，M6C碳化物呈片状。
A novel polycrystalline Ni-base superalloy was developed for land-based high temperature applications, such as isothermal forging dies and industrial gas turbines. The alloy possessed surprisingly high stress rupture life of 52 h at 1100 °C/118 MPa which is comparable to the first generation single crystal (SC) superalloy and exhibited good microstructural stability. The effects of Ta addition on the phase change, stress rupture properties and microstructural stability of the alloy were investigated. The results indicated that Ta is a γ′-former and promotes the formation of eutectic γ′. The alloys with ∼7 vol.% eutectic γ′ possess higher stress rupture life at 1100 °C/118 MPa than the alloys with higher ∼20 vol.% eutectic. However, ∼20 vol.% excessive eutectic phases will enhance the stress rupture life at intermediate temperature of 760 °C for 686 MPa but weaken high temperature stress rupture properties. The (Al + Ta) content over 14.4 at.% led to the formation of large amounts of eutectic γ′ and exceeded the solubility of W and Mo in the residue liquid pool, which then promoted the precipitation of primary α-(W,Mo) and M6C phases. Tantalum was also found as a strong MC carbides forming element. The order of ability to form monocarbide decreased from NbC to TaC to TiC. 6Al–0Ta (wt.%) alloys possessed good microstructural stability with no harmful topologically close-packed (TCP) phases being observed after thermal exposure at 850 °C/3000 h, 900 °C/1000 h. Only trace amounts of secondary plate-like M6C carbides appeared in Ta-free and 5Al–4Ta (wt.%) alloys at 1100 °C/100–500 h. However, excessive Ta addition will destabilize the alloy and large amounts of secondary plate-like M6C carbides precipitated after thermal exposure at 1100 °C. The transmission electron microscopy (TEM) and selected area electron diffraction (SAED) results showed the existence of the plate-like M6C carbides.
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DOI：
10.4028/www.scientific.net/kem.171-174.609
发表时间：
1999-10
期刊：
Key Engineering Materials
影响因子：
--
作者：
Ping Zhang;B. Watzinger;Q. P. Kong;Wolfgang Blum
通讯作者：
Ping Zhang;B. Watzinger;Q. P. Kong;Wolfgang Blum
影响因子：
2.2
作者：
Sherwin W. Yang
通讯作者：
Sherwin W. Yang
影响因子：
8.4
作者：
Chamanfar, A.;Sarrat, L.;Koul, A. K.
通讯作者：
Koul, A. K.
DOI：
10.1017/cbo9780511541285
发表时间：
2006-09
期刊：
--
影响因子：
--
作者：
R. Reed
通讯作者：
R. Reed
DOI：
10.1016/s0921-5093(99)00705-4
发表时间：
2000-04-15
影响因子：
6.4
作者：
Karunaratne, MSA;Carter, P;Reed, RC
通讯作者：
Reed, RC