The crystalline-to-amorphous transition in shock-loaded mullite Al2VI(Al2+2xSi2−2x)IVO10−x in the light of shear modulus anisotropy

Unlike the formation of shear-induced PDF-type glass lamellae in shocked mullite, the thermal decomposition of mullite following high post-shock temperatures results in a fine-grained phase assemblage consisting of corundum plus amorphous silica, and represents the most abundant transformation mechanism in the shock regime investigated (20-40 GPa). No stishovite was observed. At shock levels beyond 35 GPa thermal decomposition of mullite may occur along with PDFs within the same specimen.