Abstract
The effects of grain size and temperature on environmental embrittlement of an L12-type Ni3(Si, Ti) ordered alloy were investigated as a function of strain rate by tensile tests and scanning electron microscope fractography. Irrespective of grain size and temperature, ductile-brittle transition (DBT) occurred when the strain rate decreased. Corresponding to the DBT, fracture surfaces changed from transgranular to intergranular fracture. DBT of a coarse-grained material occurred in a higher strain rate region than that of a fine-grained material. DBT of materials deformed at 423 K occurred in a lower strain rate region than that of materials deformed at room temperature. In a very low strain rate region, an anomalous increase of tensile elongation was observed for a fine-grained material deformed at 423 K.
