Abstract
The interrelationship between grain size and hardness distributions during grain growth has been investigated for a pure iron. It was shown that the geometric mean grain diameter Dg increased during grain growth, while the standard deviation for lnD, lnσg decreased, where the grain diameter D was defined as the equivalent volume diameter. The (arithmetic) mean Vickers hardness \barHV decreased during recrystallization and growth, showing a common sigmoidal curve in the plots of \barHV versus annealing time, and the variation coefficient of hardness σHV⁄\barHV expressing the spread of the distribution also tended to decrease. The mean hardness \barHV had a better correlation with Dg−1⁄2 than with \barl−1⁄2, where \barl was the arithmetic mean length of linear intercept. Therefore, it is concluded that Dg, which is one of the mean grain sizes in three dimensions, is a more significant value of the mean grain size than \barl. It was also pointed out that the value of σHV⁄\barHV has a trend to increase with the increment of lnσg.
