Thin-Wall Debit in Creep of DS200 + Hf Alloy
Thin-Wall Debit in Creep of DS200 + Hf Alloy
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DOI：
10.1007/s11661-018-4708-y
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发表时间：
2018-06
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影响因子：
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通讯作者：
L. Mataveli Suave;Aïda Serrano Muñoz;A. Gaubert;G. Benoît;L. Marcin;P. Kontis;P. Villechaise;J. Cormier
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文献类型：
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作者：
L. Mataveli Suave;Aïda Serrano Muñoz;A. Gaubert;G. Benoît;L. Marcin;P. Kontis;P. Villechaise;J. Cormier
本文研究了定向凝固DS 200 + Hf合金在900 °C蠕变寿命中的薄壁缺陷。一系列不同的施加载荷和各种方向相对于凝固方向进行了研究。详细研究了DS 200 + Hf合金薄试样和大块试样在空气中蠕变性能的直接比较。蠕变试验结果表明，与纵向相比，沿着横向薄壁件的蠕变寿命和蠕变延性明显降低。将上述蠕变性能与单晶DS 200 + Hf的蠕变中的薄壁损失进行比较<001>，对于单晶DS 200 + Hf，几乎没有观察到蠕变寿命中的厚度减记。蠕变过程中的薄壁缺陷主要归因于晶界的优先氧化。此外，氧化碳化物被发现破裂，并在其附近发现再结晶。最后，基于实验结果，提出了一种耦合蠕变-氧化模型方法来考虑薄壁在蠕变寿命中的缺陷。该模型考虑到蠕变各向异性，通过归一化的极限拉伸应力在诺顿和Kachanov法律在这个建模框架中使用。
The thin-wall debit in creep life of the directionally solidified DS200 + Hf alloy at 900 °C has been investigated. A range of different applied loads and various directions with respect to the solidification direction was investigated. A direct comparison of creep properties in air between thin and massive specimens of DS200 + Hf was studied in detail. Creep results have shown that a substantial thin-wall debit in creep life and creep ductility is obtained along transverse directions compared with the longitudinal direction. The above creep performance was compared with the thin-wall loss in creep of the <001> single-crystal DS200 + Hf, for which almost no thickness debit in creep life was observed. The thin-wall debit in creep was mainly ascribed to the preferential oxidation of the grain boundaries. Besides, oxidized carbides were found to be cracked, and recrystallization was found in their vicinity. Finally, based on the produced experimental outcome, a coupled creep-oxidation modeling approach has been proposed to account for the thin-wall debit in creep life. This model takes into account creep anisotropy through the normalization by the ultimate tensile stress in both the Norton and Kachanov laws used in this modeling framework.