In these four regions, superhardness effect could only be generated in the region with sharp interface and epitaxial growth structure, and the maximum hardness reaches 45.8 GPa.
Hardening of the surface layers was also achieved to a significant depth (∼100 μm), with the maximum surface hardness reaching ∼20 GPa (HK), which are desirable for improved surface performance.
The maximum hardness is reached for VC coatings with C/V ratios around unity, decreasing for either higher or lower C/V ratios.
While investigating the effect of thermal ageing temperature on hardness of SiCp-reinforced 6061 Al and 2014 Al matrix composites, Song et al. (1995) observed an increase in hardness with ageing temperature, and maximum hardness was reached at 150°C to 200°C, and the composites containing 2014 Al were much harder than those with 6061 Al.
For all three alloys investigated, the hardness reached a maximum after 1 2 h aging at 500 550 °C.
The hardness reached the maximum value of 25.2 GPa at pN2 = 3.5 Pa, where the BCN films possessed the highest intensity of C B and sp3 N C bonds and the lowest fraction of sp2 h-B N bond.
The cross-section microhardness measurement indicated that the hardness reached the maxima for a cobalt content of 50 wt.% and then dropped with the increase in cobalt content.
At 706 °C, the content of γ′phase, as well as the content of nitrogen and the hardness, reaches the maximum.
The microstructure improvement at the optimized bias (− 80 V) contributed further to the enhancement in the hardness, reaching a maximum value of ~ 18.0 GPa.
The hardness reaches to its maximum at the middle of the deformation channel and decreases in the second half of the channel due to reversal straining.
