Effects of creep and oxidation on reduced modulus in high-temperature nanoindentation

详细信息    查看全文

• 作者：Yan Li^a ; ^b ; Xufei Fang^a ; ^b ; ^{thufangxufei2007@foxmail.com" class="auth_mail" title="E-mail the corresponding author} ; Siyuan Lu^a ; ^b ; Qingmin Yu^c ; Guohui Hou^d ; Xue Feng^a ; ^b ; ^{fengxue@tsinghua.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：High temperature nanoindentation ; Creep ; Oxidation ; Reduced modulus
• 刊名：Materials Science & Engineering A
• 出版年：2016
• 出版时间：15 December 2016
• 年：2016
• 卷：678
• 期：Complete
• 页码：65-71
• 全文大小：1995 K

文摘

Nanoindentation tests were performed on single crystal Ni-based superalloy at temperatures ranging from 20 °C to 800 °C in inert environment. Load-displacement curves at temperatures higher than 500 °C exhibit obvious creep inferred by increasing displacements at load-holding segments. Load-displacement curves obtained at 800 °C also display negative unloading stiffness. Examination of the microstructure beneath the indented area using Transmission Electron Microscope (TEM) reveals abundant dislocation piling up as well as oxide formation on the substrate. A method considering the creep effect is proposed to calculate the reduced modulus. In addition, a dimensionless ratio relating indentation depth and oxide film thickness is introduced to explain the oxidation effect on the mechanical properties derived from the load-displacement curves.