The δ-phase Precipitation Of GH4169 Alloy And Effect Of High Temperature Tensile Property

GH4169 alloy is nickel-base wrought superalloy which is based on the strengthened precipitation of face-centered cubic y'and body-centered quartet y" Themain phases of the GH4169 alloy are y,y', y" and 8 phase,in which, y phase is the matrix phase, y'and y"phase are strengthening phase.It's useful of an appropriate amount of 8 to control the alloy grain degrees and to improve the plasticity of alloy as well as to eliminate the sensitivity of gaps.Below 65o°C,this alloy is with high tensile strength,high yield strength and good plasticity,at the same time,with good comprehensive performance of anti-corrosion,anti-radiation,anti-fatigue and fracture toughness,and also the satisfactory performance of welding and forming,etc.According to the characteristics of the high temperature GH4169 alloy, analyze the precipitation laws of 8 phase of GH4169 alloy at different heat treatment system by the method of solution heat treatment plus aging treatment,and get the result that when the aging temperature is about 900°C,the precipitation rate of 8 phase can get a maximum value ;at the same aging temperature,with the extension of aging time,the content of 8 phase increases gradually,and its shape changes from the initial short-length rod into a needle-like,forming clostridium tissue.X-ray diffraction and optical microscopy were used to analyze the precipitation kinetics and microstructure evolution of 8 phase in GH4169 alloy.The results indicate that the sites and modes of 8 phase's nucleation were related to aging temperature.At a given aging temperature, the relationship between the precipitation content of 8phase and aging time follows Avrami equation.Through high-temperature tensile test,analysis how the content of 8 phase influenced high-temperature plastic deformation of GH4169 alloy, using scanning electron microscopy observed the organization of the fracture,fracture behavior and high-temperature deformation behavior of 8 phase.The results show that,the precipitation of 8 phase increased the tensile strength and yield limit of the alloy, and increased the resistance of deformation,thereby first increased and then decreased the plasticity of the alloy;the needle-like 8 phase is fractured to be short-length rod along the tensile direction,and is arranged neatly by a certain arc.