Vickers and Knoop Micro-hardness Behavior of Coarse-and Ultrafine-grained Titanium

The present study focuses on the relationship of hardness with grain size for commercially pure titanium (Cp-Ti) and ultra fine grained titanium (UFG-Ti) produced by equal channel angular process (ECAP) of Cp-Ti). Vickers and Knoop indentations of UFG-Ti at different loads was ∼2.5 times harder than those of Cp-Ti. X-ray diffraction (XRD) analysis showed peak broadening in UFG-Ti due to reduced grain size and micro-lattice strains. Scanning electron microscopy (SEM) revealed that ECAP had reduced the grain size of Cp-Ti by ∼10 times. Weibull statistics showed UFG-Ti with lower dispersion in hardness values compare to Cp-Ti indicating a more uniform microstructure.