Near Superhard Tungsten Carbide Via Synergistic Nanostructural Features
Abstract
Industrial application of superhard materials (Vickers hardness, HV > 40 GPa) such as diamond and cubic boron nitride is limited by high costs and complex routes of synthesis. However, recent efforts have demonstrated the potential for alternative materials with similar hard ness via microstructural refinement. Though broadly utilized for its hardness, tungsten carbide (WC) falls well short of qualification as a super hard material even in its less common but harder binderless form (HV ~ 26 GPa). Despite recent advances in sintering technology, even the smallest grained binderless WC (< 100 nm) has failed to achieve HV values above 33 GPa. In this work, multiple hardening mechanisms are exploited through a unique sintering approach assisted sintering (EC-PAS) is utilized to produce fully dense, binder less nanocrystalline WC ceramics with HV as high as 39 GPa. The unprecedented WC hardness is attributed to the combined effects of record small grain size (26 nm) and nanoscale intragranular substructures resulting from lattice deformation observed through transmission electron microscopy (TEM). The demonstration of the superposition of multiple hardening mechanisms provides a potential generalized avenue to improve hardness of ceramics beyond traditional Hall-Petch methods, yielding new classes of superhard materials.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 28, 2023
- Accession Number
- AD1218337
Entities
People
- Boris Feygelson
- Edward P. Gorzkowski
- Heonjune Ryou
- James Wollmerhauser
- Kevin J. Anderson
- Ramasis Goswami
Organizations
- United States Naval Research Laboratory