Effects of boron, zirconium and hafnium addition (up to 0.5 at %) on mechanical properties of the flow strength, ductility and fracture in Ni-20Al-10Fe intermetallic compound were extensively investigated by tension test, SIMS analysis and XPS analysis. The ductilization was found for the addition of boron but not for zirconium and hafnium. The tensile elongation at room temperature dramatically increased with increasing concentration of boron. Ni-20Al-10Fe intermetallic compound with 0.1 at % boron addition showed maximum elongation of about 48.5% at room temperature. Fracture mode of the alloy with or without zirconium and hafnium addition was intergranular fracture, but the addition of boron changed the fracture mode to transgranular. Though tensile tests were carried out in air, plastic deformation at peak temperature was found for the addition of boron but not for zirconium and hafnium. this result means that boron may be a species to suppress propensity of the intergranular fracture caused by the hydrogen atom. SIMS and XPS analysis showed that boron segregated to grain boundary. The beneficial effect of boron is in agreement with existing theories of solute segregation effects on grain boundary cohesion.
