STRUCTURE-PHASE TRANSFORMATIONS IN DISPERSIVE-HARDENING 47CRNIMO ALLOY AT HIGH TEMPERATURE DETERIORATION

Revealed peculiarities of changing of the structure of CrNiMo alloy depending on temperature and aging time.It is disclosed that discontinuous decay forming lamellas ofa-phase occurs during the deterioration of 47CrNiMo alloy in 800-900°C temperature interval. At the same time there is a change of dispersion patterns, increasing betweenlamellae distance increases the thickness of the slats. At the front there are initial stages of the reaction slat coagulation discontinuous precipitation, which leads to a drop in the strength properties of the alloy.It is ascertained that change of decay mechanism in γ–phase from discontinuous to continuous occurs after rising the deterioration temperature to 1000°C.Phase particles can be observed already after 5 minutes of aging. Further aging at this temperature increase the volume fraction of precipitates. Similar processes occur in the alloy at 1100°C. Raising the temperature as well as increasing aging time leads to coagulation of the particles isolated α-phase. Changing the decay mechanism with a continuous intermittent causes slumping that the strength properties and increased ductility.