Microstructure and tensile properties optimization of MIM418 superalloy by heat treatment

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• 作者：Lin Zhang^a ; ^{zhanglincsu@163.com" class="auth_mail" title="E-mail the corresponding author} ; Dan Li^a ; Xuanhui Qu^a ; Mingli Qin^a ; Xinbo He^a ; Zhou Li^b
• 关键词：Powder metallurgy ; Nickel based superalloys ; Precipitation ; Age hardening ; Electron microscopy
• 刊名：Journal of Materials Processing Technology
• 出版年：2016
• 出版时间：January 2016
• 年：2016
• 卷：227
• 期：Complete
• 页码：71-79
• 全文大小：5419 K

文摘

Solution plus ageing leads to the precipitation of finer and more homogeneous 纬′ precipitates in comparison to direct ageing. Solution treatment at 1220 °C eliminates the large primary 纬′ phase and replaces them with homogeneous secondary 纬′ precipitates. Coarsening of 纬′ particles according to Ostwald ripening mechanism is confirmed. An increase of the critical resolved shear stress (CRSS) is observed for the under-aged specimens, followed by a maximum of CRSS at 纬′ particle size of around 100 nm and a decrease of CRSS for the over-aged specimen. This result agrees well with the highest yield strength and microhardness of the 750 °C × 24 h aged specimens.