Abstract
Nanocrystalline(NC)W metals and alloys often exhibit higher radiation tolerance and strength than their coarse-grained counterparts.However,their thermal stability is low,making it difficult to achieve bulk NC W metals and alloys by consolidation using conventional techniques such as pressure-less sintering,hot-explosive-compaction sintering,and spark plasma sintering.Here we report the synthesis and mechanical properties of bulk NC W100-xTix(x=10 at.％-30 at.％)alloys prepared by consolidating mechanically al-loyed NC powders under a high-temperature/high-pressure condition.Adding 20 at.％-30 at.％Ti largely improves the sinterability of NC W-Ti alloy powders.The room-temperature microhardness and compres-sive yield strength of consolidated bulk NC W80Ti20 alloy are～16.9 and 6.0 GPa,respectively,which are mainly caused by grain boundary strengthening and significantly higher than those of previously re-ported W and W alloys.The ultimate compressive strength of bulk NC W80Ti20 measured between 900 and 1100℃deceases with increasing temperature.This behavior can be explained by the activation of Rachinger grain boundary sliding.No grain growth is observed in bulk NC W80Ti20 after compression at 1000℃.Theoretical calculation suggests that it is the segregation of Ti at grain boundaries that decreases the specific grain boundary free energy and makes the NC W80Ti20 alloy thermodynamically stable.
基金项目
国家自然科学基金(11935004)
国家自然科学基金(51971195)
Youth Fund Project of Science and Technology Research of Hebei Province(QN2020210)
Self Financing Project of Key Research and Development Program of Hebei Province(1621116)
河北省自然科学基金(E2019203465)
Independent Research Program of Young Teachers of Yanshan University(14LGB007)
High-Level Talents Research Program of Yanshan Universit y(606001101)
维普
万方数据