*3.3. Hardness Results*

The hardness of the green samples was not influenced by the amount of milled Ti content, simply due to the fact that these samples do not present an adequate integrity in the green state (Figure 6). The hardness of all sintered samples, which had no milled powder ranges, was between 180 and 210 HB. This hardness value corresponds to the standard hardness of the Cp-Ti grade 2 (200 HB). However, the amount of milled powder had a significant effect on the hardness. The hardness increased with an increase of the milled Ti content. The highest hardness was obtained at a sintering temperature of 850 ◦C. Higher temperatures resulted in a slight decrease in hardness. This can be explained by the recrystallization or coarsening process, which occurs above 850 ◦C, resulting in grain growth and a decrease in hardness or strength [43]. The sample that contained 10 wt.% milled powder showed the highest hardness (350 HB) sintered at 850 ◦C. This value is equal to the hardness of the Ti6Al4V [10].

**Figure 6.** Hardness of the samples with different amounts of milled Ti.
