Deformation Behavior Of Gh4169Superalloy Under High Current Density Electropulsing

Due to its magnificent high temperature strength and remarkable overall performance, superalloy keeps an important position, which can not be replaced in the fields of aviation, aerospace and many other industries. With the requirement of the performance and quality constantly improving, the degree of alloying of superalloy are also increased, so many harsh problems such as severe segregation, complicated processing course and formation difficulty of materials occured. Searching for new plastic processing theory and techniques to solve these difficult problems of superalloy is particularly important.Considering the unique effect of deformation resistance-reducing and plasticity-improving due to the existence of the electricity during the plastic deformation process in many metal materials, and referring the research and application outcomes in electroplastic drawing and rolling on stainless steel, magnesium alloy and titanium alloy, the author and the member group began to explore and experimentally adopt the electroplastic effect to the process of plastic deformation for hard-deformation superalloy. However, there is no precedent study on the application of electroplastic effect in the field of superalloy. The past application results were concentrated on the deformation resistance fall too much, and the corresponding micro-mechanism of electroplasticity has not been sufficiently invested, especially for this kind of materials such as superalloy with high-content alloying elements and complex phase precipitation. A thorough study on the discipline and micro-mechanism of electroplastic effect in superalloy is of particular importance.Therefore the electropulsing ccompanied tensile tests of GH4169alloy at room temperature and800℃were designed and carried out, and their tensile performances, plastic deformation behaviors and microstructures of different pulse current parameters were reviewed in present study.Based on present research, it is found that both the deformation resistance and tensile strength of GH4169alloy with adding of electropulsing on the tensile specimens became lower than that without electropulsing at room temperature, and the decline growed larger with the pulse current density increased and the frequency elevated constantly. In the case of840A/mm2,2Hz,30μs electropulsed tensile test, the maximum deformation resistance of the alloy drops up to14%compared to that without electropulsing. With the microstructure analysis, it is clear that the dislocation density has been significantly reduced with the electropulsing on the tensile specimens.At800℃, the tensile strength of GH4169alloy will be larger decreased with the electropulsing compared with that without electropulsing, at the same time, the elongation can be significantly increased. With the case of500A/mm2,10Hz,30μs electropulsing, the tensile strength is reduced about77.8%compared with that without electropulsing, and the elongation is increased up to750.2%. With the microstructure analysis, it is noticed that the dynamic recrystallization temperature of GH4169alloy can be significantly lowed with electropulsing treatment, which the dynamic recrystallization can take place at a much more lower temperature.