STRENGTH, HARDNESS AND FRACTURE-TOUGHNESS OF A COMPLEX NICKEL SILICIDE CONTAINING DUCTILE-PHASE PARTICLES

Measurements have been made at room temperature of the strength and fr acture toughness of a complex nicker silicide containing particles of a ductile phase. The matrix was either a single-phase L1(2) distorted Ni3Si (beta(2)) or a two-phase Ni3Si (beta(1)) and Ni31Si12 (gamma) mi xture. The particles were a solid solution of Ni(Si) encased within a rim of beta(1); they contained a dispersion of beta(1) precipitates. T he principal variable was the particle size, and this had little effec t on the properties. The results show that the compressive yield stren gth (similar or equal to 1200 MPa), the compressive ductility (2-10%) and the fracture toughness (17 +/- 3 MPa m(1/2)) are relatively high. The toughness and ductility are attributed to the plastic deformation and ductile fracture of the crack-stopping Ni(Si) particles.