Influence of heat treatment on anisotropic creep behavior of aluminide coating on a Ni-base single crystal superalloy
Influence of heat treatment on anisotropic creep behavior of aluminide coating on a Ni-base single crystal superalloy
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DOI：
10.1016/j.matdes.2013.04.101
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发表时间：
2013-12
影响因子：
8.4
通讯作者：
F. Latief;K. Kakehi
中科院分区：
文献类型：
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作者：
F. Latief;K. Kakehi
研究了热处理对不同表面取向镍基单晶高温合金铝化物涂层蠕变行为的影响。试件在氩气环境下进行1000℃、5h的包渗铝处理。然后在 900 °C 的温度和 320 MPa 的应力下对涂层样品进行拉伸蠕变测试。为了确定铝化物涂层的效果，还对裸样品进行了测试。渗铝处理降低了镍基单晶高温合金的蠕变强度。固溶热处理工艺对镍基单晶高温合金的蠕变行为有很大影响。固溶处理与后续的二次时效处理相结合，γ′相的形态更加规则，γ′相的分布更加均匀，可有效提高镍基单晶高温合金的蠕变强度。此外，无论是在镀铝样品还是裸露样品中，{1 0 0} 样品都比那些 {1 1 0} 样品表现出更好的蠕变寿命。各向异性蠕变行为主要是由样本两个表面方向之间的 {1 1 1} <1 0 1> 滑移系统的不同排列引起的。 {1 0 0}和{1 1 0}侧表面样本之间的蠕变断裂寿命差异在样本 STA 中比在样本 A 中更明显，因为 γ/γ' 微观结构的均匀化促进了 {1 1 1} <1 0 1> 滑移系统的变形，从而导致蠕变行为的各向异性。此外，微观结构的变化也被认为是蠕变寿命降低的因素之一。此外，TCP相的形成、TCP相渗透的深度以及涂层到基体区域的硬度值梯度将是阐明镀铝镍基单晶高温合金各向异性蠕变行为的附加因素。
The influence of heat treatment on creep behavior of aluminide coating on a Ni-base single crystal superalloy with different surface orientations was examined. The specimens were coated by pack aluminizing treatment at 1000 °C for 5 h under argon environment. The coated specimens were then tested by the tensile creep test at a temperature of 900 °C and a stress of 320 MPa. To determine the effect of aluminide coating, the bare specimens were also tested. The aluminizing treatment decreased the creep strength of Ni-base single crystal superalloy. The solution heat treatment procedures had a great impact on the creep behavior of Ni-base single crystal superalloy. The combination of solution treatment and subsequent double aging treatment was effective to improve the creep strength of Ni-base single crystal superalloy because of more regular the shape of γ′ precipitates and more homogeneous distribution of γ′ precipitates. In addition, the {1 0 0} specimens showed a better creep lives than those {1 1 0} specimens both in aluminized specimens and bare specimens. The anisotropic creep behavior was primarily induced by the different arrangement of {1 1 1} <1 0 1> slip systems between the two surface orientations of the specimens. The difference in creep rupture lives between {1 0 0} and {1 1 0} side-surface specimens was more pronounced in the specimens STA than in the specimens A because of homogenization of the γ/γ′ microstructure promoted the deformation by {1 1 1} <1 0 1> slip system which leads to anisotropy of creep behavior. Moreover, the change in microstructures was also considered as one of factors for the decrease of creep life. Besides, the formation of TCP phase, the depth of TCP phase penetration and the gradient of hardness values in the coating to the substrate regions would be additional factors to clarify the anisotropic creep behavior in aluminized Ni-base single crystal superalloy.