Hot Deformation Behavior And Microstructure Evolution Of The Pure Nickel

Thermally conductive properties of the pure nickel with high and low air content and the vapor pressure and good corrosion resistance, plastic processing machinery and welding performance, is widely used in electrical components, petroleum chemical industry, food industry, aerospace and military components, and other fields, but the research on the hot deformation behavior of pure nickel does very little, and thus received extensive attention of materials researchers.Pure nickel N6 this study as the research object, using Gleeble-3800 hot simulation experiment machine, respectively for the cylinder of high temperature hot compression test,(deformation temperature is 700-1100℃, strain rate is 0.001 to 10 s-1, the dependent variable was 40% and 55%) high temperature hot compression tests in plane strain,(deformation temperature is 700-1100℃, strain rate is 1 to 40 s-1, variable should be 70%).Combined with hot compress test data, using the cubic spline interpolation method is pure nickel N6 materials under different deformation parameters of hot working diagram. Using linear regression to build pure nickel N6 at high temperature in the process of plastic deformation rheological constitutive equation of stress, the constitutive model of pure nickel N6.At the same time, by means of optical metallographic microscope(OM) and transmission electron microscopy(TEM), and other testing means, to pure nickel N6 under the condition of different deformation microstructure evolution law of the research and analysis of the system. The main results were as follows:Through the pure nickel N6 plate high temperature hot compressive deformation behavior research, the main factors affecting its rheological stress change is the deformation temperature and strain rate, variable should be almost no effect on it. According to the hot compression test data, made the pure nickel N6 hot working diagram, and analyzes the processing figure and calculate the data, determine the pure nickel N6 under different deformation condition and the reasonable processing rheological instability area. Based on the established thermoplastic processing figure, comparing the rheological instability area under the deformation parameters and reasonable processing parameters of the rupture, deformation reasonable processing parameters of the uniform organization; While degeneration under the parameters of rheological instability region organization is disorder, grain sizes. Established the pure nickel N6 thermal deformation constitutive model of plane strain. Through multivariate nonlinear fitting, the establishment of pure nickel N6 flow stress of cubic polynomial model containing variables should be epsilon. By experimental verification, the model used to calculate the rheological stress and the measured values of the basic meet, meet the requirements of engineering calculation.