INFLUENCE OF THE STOICHIOMETRY ON THE MECHANICAL PROPERTIES OF SPINEL (Al2O3)nMgO SINGLE CRYSTALS N. DOUKHAN, R. DUCLOS and B. ESCAIG J. Phys. Colloques, 37 C7 (1976) C7-566-C7-571 DOI: 10.1051/jphyscol:19767132