Pressureless two-step sintering of ultrafine-grained refractory metals:Tungsten-rhenium and molybdenum

作     者：Zhongyou Que Zichen Wei Xingyu Li Lin Zhang Yanhao Dong Mingli Qin Junjun Yang Xuanhui Qu Ju Li Zhongyou Que;Zichen Wei;Xingyu Li;Lin Zhang;Yanhao Dong;Mingli Qin;Junjun Yang;Xuanhui Qu;Ju Li

作者机构：Beijing Advanced Innovation Center for Materials Genome EngineeringInstitute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China Department of Nuclear Science and EngineeringMassachusetts Institute of TechnologyCambridgeMA 02139USA Department of Materials Science and EngineeringMassachusetts Institute of TechnologyCambridgeMA 02139USA 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2022年第126卷第31期

页      面：203-214页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：supports by the Natural Science Foundation of China(52074032 51974029 52131307 52071013)and“111”Project(No.B170003).Y.D.and J.L.acknowledge the support by Eni S.p.A.through the MIT Energy Initiative 

主　　题：Powder metallurgy Refractory metals Porosity Two-step sintering Grain growth 

摘      要：The challenge of sintering ultrafine-grained refractory metals and alloys to full density is hereby addressed by pressureless two-step sintering in tungsten-rhenium alloy and pure molybdenum. Using properly processed nano powders(~50 nm average particle size), we are able to sinter W-10Re alloy to 98.4% density below 1200 ℃ while maintaining a fine grain size of 260 nm, and sinter molybdenum to 98.3% density below 1120 ℃ while maintaining a fine grain size of 290 nm. Compared to normal sintering,two-step sintering offers record-fine grain sizes and better microstructural uniformity, which translates to better mechanical properties with higher hardness(6.3 GPa for tungsten-rhenium and 4.0 GPa for molybdenum, both being the highest in all pressurelessly sintered samples of the respective material system)and larger Weibull modulus. Together with our previous demonstration in tungsten, we believe that twostep sintering is a general effective method to produce high-quality fine-grained refractory metals and alloys, and the lessons learned here are transferable to other materials for powder metallurgy.