Study On The Constitutive Relations Of Ni₃Al-Based Intermetallics Compound

IC10 alloy is a new high temperature material. It will be the ideal high temperature material of aerostat for the next generation, because of its low density,high melting point and good plasticity. It will be widely used in the future. The study on constitutive models is the fundament of structural design. At present, the major works are focused on the technics of material performance. It's important to research constitutive relations of the IC10 alloy.This paper is to obtain stress-stain curves of IC alloy under a wide temperature range and a strain-rate range, and to set up the constitutive relation of IC10 alloy by experimental data on the base of Johnson-Cook constitutive modelFirstly, tension test was done with MTS device to obtain the stress-stain curves of IC10 alloy under different temperature(20～900℃) and strain rate(10-2～10-5/s). The test results showed that under the fixed the strain rate of 10-4/s, the flow stress of IC10 alloy was decreased with the increase of temperature(600~900℃) in general, the flow stress was increased with strain rate increased at 900℃. At 600~700℃, the value of E,σs,σb were about 110GPa,800MPa and 1100MPa respectively. With the strain rate increased, the value of E andσb decreased, but the value ofσsdecreased slowly, then increased, at last it reduced rapidly. It was concluded that the mechanical properties of IC10 alloy was sensitive to both temperatures and strain rate at high temperature.Some tensile fractures of IC10 were analyzed. During the process of the tensileness, macro-properties of ductile frature and micro-properties of classical dimple coalescence fracture was produced. It showed that IC10 alloy is good plasticity material under high temperature.At last, based on the analysis of different deformation mechanism, the Johnson-Cook constitutive model and the modified one of deformation mechanism including hardening and dynamic recrystallization were obtained by fitting with experimental data at different temperature and strain rate range. The models can describe the plastic constitutive relation of IC10 alloy ranging from 20~700℃at the same strain rate and strain rate of 10-2～10-4/s at 900℃. The experimental results showed that the modified Johnson-Cook constitutive model was more effective. And this modified one widened its original utilization.