^MECHANICAL PROPERTIES AND MICROSTRUCTURES OF TWO Ni_3Al ALLOYS
两种含硼Ni3Al合金的微观组织与力学性能

The microstructures and mechanical properties of two polycrystalline alloys, a Ni_3Al(0.6 at- %B) alloy and a Ni_3Al(1 .0 at-%B) alloy. are studied. The Ni_3Al(0.6 B)is a single phase alloy whereas the Ni_3Al(1.0 B) consists of few boride eutectic at the grain boundaries. Tensile tests and high cycle fatigue tests at room temperature are carried out in air.The results indicate that the fatigue resistance of the Ni_3Al(0.6B) alloy is higher than that of the Ni_3Al(1.0B) alloy. although, the latter is much higher than the former in tensile strength. The characteristics of fatigue crack initiation and propagation in the two Ni_3Al(B) alloys are different.