Study On Dynamic Mechanical Behaviors Of GH4169 Nickel Based Superalloy

As a kind of material with good high-temperature mechanical properties, thermal process and welding performance, GH4169 nickel based superalloy has been widely used in hot end components of aero engine. In this paper, dynamic mechanical behaviors of GH4169 were studied at different temperature and strain rate by the Split Hopkinson Pressure Bar(SHPB) and single-pulse torsional Split Hopkinson Bar. Metallographic observation method was used to analyze its deformation of grain. The contents and results are as follows:1.Dynamic compression tests of two different heat treatment methods including solid solution and aging are carried out at different temperatures and strain rates by the Split Hopkinson Pressure Bar. Results show that the strain rate effect and work-hardening phenomenon exist in the two kinds of heat treatment material, the work-hardening phenomenon of solid solution GH4169 is more obvious than aging GH4169 but the strength of it is lower than aging ones. The temperature will affect the strength and working hardening of the solid solution GH4169 superalloy.2.The modified Johnson-Cook constitutive equation is used to describe the different strain rate range of solid solution GH4169 deformation behavior with a good agreement, but only fitted well within a certain strain range at elevated temperature because of the softening effect of material.4. Dynamic torsion tests of solid solution GH4169 are studied at different shear rate. The Results indicate that strain rate effect of solid solution GH4169 also happened in shear deformation, the shear bands will propagate and then lead to shear failure when strain beyond critical shear strain.5.The microscopic deformation mechanism of solid solution and aging GH4169 superalloy are studied by metallographic observation, the observation results show that different deformation of grain and the number of delta phase lead to the different strength and work-hardening of solid solution and aging GH4169.