High-pressure strength of nanocrystalline tantalum carbide (TaC) studied at a non-hydrostatic compression

• High-pressure strength and plastic properties of nanocrystalline tantalum carbide have been investigated up to 65.5 GPa.
• The bulk modulus of nano-TaC is K0 = 433 ± 7 GPa with K′0 fixed at 4.0.
• The nano-TaC starts to yield at high pressure of ~ 20 GPa.
• The yield strength of nano-TaC reaches a value of ~ 22 GPa at the highest pressure.

High-pressure strength and plastic properties of nanocrystalline tantalum carbide (nano-TaC) have been investigated by using synchrotron radiation up to 65.5 GPa. Nano-TaC shows a bulk modulus of K0 = 433 ± 7 GPa with K′0 fixed at 4.0. It is close to that of diamond and is higher than the results from micron-TaC. In its plastic deformation behavior, nano-TaC starts to yield a plastic deformation at around 20 GPa, and the yield strength of nano-TaC increases with pressures and reaches a value of ~ 22 GPa at the highest pressure in our test. The high-pressure strength of nano-TaC is comparable to that of other superhard metals such as B6O, c-BC2N and γ-Si3N4. The first-principle DFT calculations confirm a lower bulk modulus for micron-TaC.