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

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 K-0 = 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 similar to 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 gamma-Si3N4. The first-principle DFT calculations confirm a lower bulk modulus for micron-TaC. (C) 2013 Elsevier Ltd. All rights reserved.