ABSTRACT
In Chapters 19 and 20, we discussed the nanohardness of shock-recovered fragments of a coarse-grain (≈10 μm), high-density (3.978 g⋅cc−1) alumina obtained after a carefully conducted flyer-plate shock experiment [1] at a shock pressure of 6.5 GPa, and we also compared the results for as-sintered alumina ceramics. Then, we tried to give an explanation for the presence of a strong indentation size effect (ISE) in shock-recovered alumina fragments obtained in that study [1]. In this chapter, however, we shall discuss the nanohardness and ISE of alumina ceramic shocked at very high gas-gun impact pressure of about 12 GPa at a very high strain rate of more than 104 s−1. For the sake of discussion and brevity, we shall call the shocked alumina samples as SA. Further, we shall compare the results with those of the asreceived alumina (ARA). The details of the experimental methods have been discussed already in Chapter 9.
