摘要
Continuously improving the mechanical properties of ultra-high-temperature ceramics(UHTCs)is a key requirement for their future applications.However,the mechanical properties of conventional UHTCs,HfB_(2) and ZrB_(2),remain unsatisfactory among transition metal light-element(TMLE)compounds.TiB_(2) has superior mechanical properties compared to both HfB_(2) and ZrB_(2),but suffers from inherent brittleness and limited oxidation resistance.In this work,low-content solidsolution strengthening was used to fabricate dense samples of Tix(Hf/Zr)_(1-x)B_(2)(THZ)under high pressure and high temperature(HPHT).Compared to pure TiB_(2),Ti_(0.94)(Hf/Zr)0.06B_(2) exhibits a significant 38.8%increase in oxidation resistance temperature(950℃),while Ti_(0.91)(Hf/Zr)_(0.09)B_(2) shows a notable 28%enhancement in fracture toughness(5.8 MPa·m^(1/2)).The synergistic effect of a dual-atom solid-solution results in local internal stress and anomalous lattice contraction.This lattice contraction helps resist oxygen invasion,thereby elevating the oxidation resistance threshold.Additionally,the internal stress induces crack deflection within individual grains,enhancing toughness through energy dissipation.This work provides a new strategy for fabricating robust UHTCs within TMLE systems,demonstrating significant potential for future high-temperature applications.
基金
support from the Program for the Development of Science and Technology of Jilin Province(Grant No.SKL202402004)
the Jilin Province Major Science and Technology Program(Grant No.20240211002GX)
the Open Research Fund of the Key Laboratory of Functional Materials Physics and Chem-istry of the Ministry of Education(Jilin Normal University,Grant No.202405).
