Compression behavior of nanocrystalline TiN

• No phase transition was observed during compression for each sample.
• A fit of the pressure (P) versus volume data to a second Birch–Murnaghan equation yielded the following parameters for 16 nm, 34 nm and 80 nm, zero-pressure volume, V0=75.77 Å3, 75.98 Å3 and 76.06 Å3, bulk modulus, B0=320(7) GPa, 338(6) GPa and 287(3) GPa, respectively.
• The P–V data of 16 nm is relatively discrete at P>20 GPa compared with those of 34 nm, 80 nm and previous works.
• The full width at half maximum of 16 nm continues to increase, whereas those of 34 nm and 80 nm become almost constant when the pressure reaches a certain value.

We have investigated the size-dependent high pressure behavior of nanocrystalline TiN using an angle-dispersive X-ray diffraction technique in a diamond-anvil cell at room temperature. No phase transition was observed during compression for each sample. A fit of the pressure versus volume data to a second Birch–Murnaghan equation yielded the following parameters for 16 nm, 34 nm and 80 nm, zero-pressure volume, V0=75.77 Å3, 75.98 Å3 and 76.06 Å3, bulk modulus, B0=320(7) GPa, 338(6) GPa and 287(3) GPa, respectively. This result along with a reanalysis of previous studies on TiN indicates that the bulk modulus first increases and then decreases with decreasing grain size. The compressibility of TiN has a minimum at ~34 nm.