Influence of coarsened and rafted microstructures on the thermomechanical fatigue of a Ni-base superalloy
Influence of coarsened and rafted microstructures on the thermomechanical fatigue of a Ni-base superalloy
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DOI：
10.1016/j.ijfatigue.2015.08.001
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发表时间：
2015-12-01
影响因子：
6
通讯作者：
Gravett, P. W.
中科院分区：
文献类型：
--
作者：
Kirka, M. M.;Brindley, K. A.;Gravett, P. W.
ni基高温合金在使用过程中组织的老化主要表现为γ′相的粗化和沉淀。研究了这些不同时效组织对连续循环（CC）和蠕变疲劳（CF）下热机械疲劳（TMF）的影响。通过加速时效和预蠕变处理，研究了三种不同时效组织：无应力粗化γ′。方向垂直于加载方向的筏板（n筏）和方向平行于加载方向的筏板（p筏）。在大多数条件下，时效组织的抗TMF能力低于未时效组织；然而，也有例外。与原始材料相比，在CC和CF条件下，无应力粗化和N-raft微观结构都会导致TMF寿命降低。在CC条件下，P-raft组织也导致了TMF寿命的降低；然而，在CF条件下，寿命比原始材料有所增加。讨论了这些差异，并假设这些差异与γ通道中的位错与γ′沉淀的相互作用有关。(C) 2015 Elsevier Ltd.版权所有。
The aging of the microstructure of Ni-base superalloys during service is primarily characterized by coarsening and rafting of the gamma' precipitates. The influence of these different aged microstructures on thermomechanical fatigue (TMF) under either continuously cycled (CC) and creep-fatigue (CF) was investigated. Three different aged microstructures, generated through accelerated aging and pre-creep treatments, were studied: stress-free coarsened gamma'. rafted with orientation perpendicular to loading direction (N-raft), and rafted with orientation parallel to loading direction (P-raft). Under most conditions, the aged microstructures were less resistant to TMF than the virgin microstructure; however, there were exceptions. Both stress-free coarsened and N-raft microstructures resulted in a reduction in TMF life under both CC and CF conditions in comparison to the virgin material. P-raft microstructure also resulted in reduction in TMF life under CC conditions; however, an increase in life over that of the virgin material was observed under CF conditions. These differences are discussed and hypothesized to be related to the interactions of the dislocations in the gamma channels with gamma` precipitates. (C) 2015 Elsevier Ltd. All rights reserved.