MICROSTRUCTURE AND MECHANICAL PROPERTIESOF DUAL TWO-PHASE INTERMETALLIC ALLOYS COMPOSED OF GEOMETRICALLY CLOSE PACK ED Ni_3AI AND Ni_3V STRUCTURES

摘要

The microstructures and hardness property of dual two-phase intermetallic alloys that are composed of various kind of volume fractions of geometrically closed packed (GCP) Ni_3Al(Ll_2) and Ni_3V(D0_(22)) phases was studied. The hardness of dual two-phase intermetallic alloys was basically explained by mixture rule in hardness between primary Ni_3Al precipitates and eutectoid region. Nb and Ti addition raised hardness of dual two-phase intermetallic alloys by solid solution hardening in the constituent phases. Additional hardening arising from interfacial area between primary Ni_3Al precipitates and eutectoid region was found. As temperature increases, the additional hardening monotonously decreased for the base and Nb added alloys but little decreased for the Ti added alloy.