Dependence of the mechanical properties of a P/M nickel alloy on deformation temperature and rate

Conclusions

At room temperature the strength of ZhS6 nickel alloy produced by the granule metallurgy method is 1.5 times higher and its plasticity 3–4 times higher than those of the same alloy produced by the standard casting process. The P/M alloy remains superior in strength to the cast alloy up to temperatures of the order of 750–800°C, above which the strength characteristics of the P/M alloy fall below the level of properties of the cast material. The deformation of the P/M alloy varies in character depending on testing temperature, and three types of specimen fracture are possible: brittle fracture without waist formation in the temperature range 20–700°C, fracture with waist formation at 700–1000°C, and plastic deformation along the whole specimen length above 1000°C. At temperatures of 1000–1150°C the P/M alloy exhibits superplasticity: At low rates of deformation its elongation attains several hundred percent when the load is about 0.1σ_0.2. The elongation of the specimen, load applied, and type of stress-strain diagram depend to a large extent on the rate of deformation: As the latter is decreased, δ_e sharply grows and the load diminishes.