Predominantly 6H <0001> SiC single crystals have been implanted with nitrogen and aluminum at 300°K. The effects of implantation and post-implantation annealing at 573–1173°K have been characterized by Rutherford backscattering/channeling, microhardness measurements and transmission electron microscopy. Even at 1173°K, defect annealing was inhibited in amorphized regions. Progressive damage recovery as the anneal temperature was increased was otherwise generally observed. Fluences predicted by the critical damage energy of 2 × 1021 keV/cm3 did not quite produce amorphization to x = 0. In the as-implanted specimens, decreasing hardness was observed with increasing fluence. Significant surface softening (∼ 33% hardness reduction) was achieved at the highest aluminum fluence (5 × 1015 Al/cm2) and was stable at temperatures < 893°K.