Saturation of yield stress and embrittlement in fine lamellar TiAl alloy
Saturation of yield stress and embrittlement in fine lamellar TiAl alloy
复制标题
细片状TiAl合金的屈服应力饱和和脆化
DOI：
10.1016/s0921-5093(01)01565-9
复制
发表时间：
2002
期刊：
影响因子：
6.4
通讯作者：
Hiroyuki Sato
中科院分区：
文献类型：
--
作者：
K. Maruyama;G. Suzuki;H. Kim;Mayumi Suzuki;Hiroyuki Sato
Sun提出，层状材料的屈服应力通过细化层间距而增加，但增加有上限。本文旨在通过室温和950 K条件下全层状Ti-39 mol% Al合金的实验结果来检验这一预测。片层间距在20 ~ 590 nm之间变化，晶粒尺寸保持在90 μm。Hall-Petch关系在片层间距和合金的屈服应力之间成立。然而，屈服应力在1GPa的水平下饱和，这是在约100 nm的临界片层间距以下实现的。这些结果支持了Sun的预测。Hall-Petch斜率，临界片层间距和饱和应力水平可以解释一致的位错在片层边界的堆积模型。与对屈服应力的有益影响相反，层状细化使层状材料的延展性劣化。
It has been proposed by Sun that the yield stress of lamellar materials is increased by refinement of lamellar spacing but there is an upper limit to the increase. This paper aims at the examination of this prediction by experimental results of a fully lamellar Ti–39 mol% Al alloy tested at room temperature and at 950 K. The lamellar spacing is varied from 20 to 590 nm, while keeping the same grain size of 90 μm. The Hall–Petch relation holds between the lamellar spacing and the yield stress of the alloy. However, the yield stress saturates at a level of 1 GPa, which is achieved below a critical lamellar spacing of about 100 nm. These results support the prediction by Sun. The Hall–Petch slope, the critical lamellar spacing and the saturation stress level can be explained consistently by a pile-up model of dislocations at lamellar boundaries. Contrary to the beneficial effect on the yield stress, the lamellar refinement deteriorates ductility of the lamellar material.