Effect of Mo content on microstructure and stress-rupture properties of a Ni-base single crystal superalloy

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• 作者：Yunfei Liang ^{yunfei_liang@buaa.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Shusuo Li ; ^{lishs@buaa.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Cheng Ai ; Yafang Han ; Shengkai Gong
• 关键词：Ni-base single crystal superalloy ; Mo content ; Stress-rupture property
• 刊名：Progress in Natural Science
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：26
• 期：1
• 页码：112-116
• 全文大小：2075 K

文摘

The additional 1.5 wt% Mo was added in a Ni-base single crystal (SC) alloy with the composition of Ni–6.5Al–8.0Mo–2.4Cr–6.2Ta–4.9Co–1.5Re–(0.01–0.05)Y (wt%) to study the effect of Mo content on the microstructure and stress-rupture properties. The creep and stress-rupture tests under the conditions of 850 °C/500 MPa and 1100 °C/130 MPa were conducted, and the microstructure of as-cast, heat treated and stress ruptured specimens were analyzed. It was found that the 1.5 wt% Mo addition enhanced the stress-rupture lives at both intermediate (850 °C) and high (1100 °C) temperatures. The microstructure analysis showed that adding 1.5 wt% Mo in the basic alloy affected the microstructure dramatically, i.e., the Mo-rich phases formed in the specimens of as-cast and stress-ruptured specimens. It is considered that the improvement of the stress-rupture lives is duo to the strengthening effect of Mo to both γ and γ′ phases and the decrease of stacking fault energy, diffusion constant and dislocation spacing. The Mo-rich phases precipitated under condition of 1100 °C/130 MPa did not affect the creep and stress-rupture properties obviously in the present study.