Dispersoids and gamma ' precipitates in an ultrafine grained Rene 88DT-5vol.% Y2O3 alloy with outstanding thermal stability
Dispersoids and gamma ' precipitates in an ultrafine grained Rene 88DT-5vol.% Y2O3 alloy with outstanding thermal stability
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分散体%20and%20gamma%20'%20沉淀%20in%20an%20超细%20grained%20Rene%2088DT-5vol.%%20Y2O3%20合金%20with%20outstanding%20热%20稳定性
DOI：
10.1016/j.matchar.2018.04.027
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发表时间：
2018
影响因子：
4.7
通讯作者：
Lavernia Enrique J
中科院分区：
文献类型：
--
作者：
Xia Tian;Yang Chao;Zeng Wei;Xie Yuehuang;Zhang Yiwen;Zhang Deliang;Zhu Guoliang;Shu Da;Lavernia Enrique J
我们报道了一种超细晶（UFG）René 88 DT-5vol.%采用高能机械球磨和粉末热机械固结工艺制备了具有高热稳定性的Y2 O3合金。挤压态样品由平均尺寸为122 nm的超细晶γ基体组成，基体中分散着平均尺寸为12.6 nm的Y 4Al 2 O 9纳米颗粒和尺寸约为150 nm的TiN颗粒。该合金的UFG显微组织显示出优异的热稳定性，在1120 °C（0.85Tm，其中T是在开尔文标度下的合金的固相线温度）下保持2 h和随后在760 °C下保持16 h后，平均晶粒尺寸仅从122 nm略微增加到145 nm。通过实验和JMatPro软件计算证实，由于Y 4Al 2 O 9和TiN弥散相的形成消耗了γ′形成元素Ti和Al，热处理后试样显微组织中的γ′相含量显著减少。此外，热处理后的UFG René 88 DT-5vol.%中γ '沉淀物的尺寸也急剧下降至20-30 nm在相同的热处理条件下，Y2 O3合金的尺寸为100-150 nm，而不含Y2 O3的基体合金的尺寸为100-150 nm。
We report on an ultrafine-grained (UFG) René 88DT-5vol.%Y2O3alloy with a high thermal stability fabricated through high energy mechanical milling and thermomechanical powder consolidation. The as-extruded sample consists of an ultrafine grained γ matrix with an average size of 122 nm with Y4Al2O9nanoparticles (average size: 12.6 nm) and TiN particles (size about 150 nm) being dispersed in the matrix. The UFG microstructure of the alloy showed an outstanding thermal stability with the average grain size only increasing slightly from 122 to 145 nm after holding at 1120 °C (0.85Tm, whereTmis the solidus temperature of the alloy in Kelvin scale) for 2 h and subsequently holding at 760 °C for 16 h. Due to the consumption of γ′ forming elements, Ti and Al, by the formation of the Y4Al2O9and TiN dispersoids, the content of γ′ precipitates in the microstructure of the heat treated sample is significantly reduced, as confirmed by experimentation and calculation using the JMatPro software. Additionally, the size of γ′ precipitates also sharply decreased to 20–30 nm in the heat treated UFG René 88DT-5vol.%Y2O3alloy, in contrast to a size of 100–150 nm in the Y2O3-free base alloy under the same heat treatment condition.