Influence of the powder particle size on tensile properties of Ni3Al processed by rapid solidification and hot isostatic pressing

The mechanical properties of PM Ni3Al with boron additions as a function of the powder particle size have been investigated. The study has been carried out by tensile tests from room temperature up to 1000 °C. The rapidly solidified powders have been produced by argon atomization. Cans with different powder particle sizes, < 25 μm, 25–50 μm, 50–100 μm and 100–200 μm were hipped at 1100 and 1200 °C under 150 MPa. The microstructure of the consolidated material consists of ordered Ni3Al. The hardness and tensile properties of compacts depend on particle size and the effect is more evident for the low-temperature range. The material obtained from the smaller size powders exhibited the best mechanical behaviour. A dependence between tensile properties, especially elongation to failure, and the curvature radius of the flat tensile sample has been found. It has been demonstrated that the use of a small curvature radius gives more representative values of tensile properties as the deformation is restricted to the gauge length.