ELASTIC AND PLASTIC BEHAVIOR OF SUBMICROMETER-SIZED POLYCRYSTALLINE NIAL

The elastic properties and flow behavior of Ni-48.4Al have been charac terized by means of the miniaturized disk-bend test (MDBT), Vickers in dentation and measurements of the longitudinal and transverse velociti es of sound. Young's modulus, shear modulus, yield stress and fracture stress have been determined as a function of grain size ranging from 30 nm to 2 mu m. It has been found that nanometer-sized polycrystallin e Ni-48.4Al is essentially brittle at room temperature and 700 K. Elas tic moduli obtained suggest no elastic weakness of interfaces. Nanomet er-sized Ni-48.4Al samples appear to behave as ceramic material. Copyr ight (C) 1996 Acta Metallurgica Inc.