Challenge of change of alloy properties during service life of extra safety parts was always considered by industrialists and consequently researchers. Fuselage and wings of airplane repeatedly in ascent and descent is affected respectively by cooling to -55 0C and heating to room temperature. Hence, the effect of above temperature changes on tensile properties is unknown. In this study in laboratory, the situation of airplane body is tried to simulate and then the changes of microstructure and consequently the changes of tensile properties and hardness after holding for 10 and 4 hours were studied respectively in temperature -600C and -1960C. Results showed that by
using of sub-zero treatment, hardness is without change but tensileproperties are increased to control sample and when the cooling rate was low (≈1 degree per minute),
کلید واژگان :
Population density of particles, Liquid nitrogen, Sub-Zero treatment Toughness
