缩进
材料科学
钨
软化
氮化物
复合材料
冶金
图层(电子)
作者
Cheng Lü,Quan Li,Yanming Ma,Changfeng Chen
标识
DOI:10.1103/physrevlett.119.115503
摘要
Transition-metal light-element compounds are a class of designer materials tailored to be a new generation of superhard solids, but indentation strain softening has hitherto limited their intrinsic load-invariant hardness to well below the 40 GPa threshold commonly set for superhard materials. Here we report findings from first-principles calculations that two tungsten nitrides, hP4-WN and $\mathrm{hP}6\text{\ensuremath{-}}{\mathrm{WN}}_{2}$, exhibit extraordinary strain stiffening that produces remarkably enhanced indentation strengths exceeding 40 GPa, raising exciting prospects of realizing the long-sought nontraditional superhard solids. Calculations show that hP4-WN is metallic both at equilibrium and under indentation, marking it as the first known intrinsic superhard metal. An x-ray diffraction pattern analysis indicates the presence of hP4-WN in a recently synthesized specimen. We elucidate the intricate bonding and stress response mechanisms for the identified structural strengthening, and the insights may help advance rational design and discovery of additional novel superhard materials.
科研通智能强力驱动
Strongly Powered by AbleSci AI