Transparent nanocrystalline bulk alumina obtained at 7.7 GPa and 800 ¡ãC

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• 作者：Norimasa Nishiyama ; Takashi Taniguchi ; Hiroaki Ohfuji ; Kimiko Yoshida ; Fumihiro Wakai ; Byung-Nam Kim ; Hidehiro Yoshida ; Yuji Higo ; Astrid Holzheid ; Oliver Beermann ; Tetsuo Irifune ; Yoshio Sakka ; Ken-ichi Funakoshi
• 关键词：Alumina ; Transparent ; Nanocrystalline ; High pressure ; Hardness
• 刊名：Scripta Materialia
• 出版年：2013
• 出版时间：September, 2013
• 年：2013
• 卷：69
• 期：5
• 页码：362-365
• 全文大小：1196 K

文摘

Transparent nanocrystalline bulk alumina was obtained at 7.7 GPa and 800 ¡ãC. The alumina has an average grain size of ¡«150 nm and an in-line transmission of 71 % for a wavelength of 640 nm and a thickness of 0.8 mm. The values of microhardness and fracture toughness were found to be 25.5 ¡À 0.3 GPa and 2.9 ¡À 0.3 MPa m^1/2, respectively. The hardness value is consistent with the previously determined Hall-Petch relation and fracture toughness is independent of grain size.