Testing device and method for determining metal rheological instability conditions

Abstract

The invention discloses a testing device and a method for determining metal rheological instability conditions. The method comprises a pressure loading device, a pressure head and an industrial mould, wherein the industrial mould comprises an upper mould and a lower mould; the upper mould is provided with a plurality of upper mould convex platforms and a plurality of upper mould grooves, the upper mould convex platforms and the upper mould grooves are arranged at intervals, and the heights of the upper mould convex platforms can be adjusted; the lower mould is provided with a plurality of low mould convex platforms and a plurality of low mould grooves, and the low mould convex platforms and the low mould grooves are arranged at intervals; the upper mould convex platforms and the low mould grooves are coupled with each other, and the upper mould grooves and the low mould convex platforms are coupled with each other; the pressure head is connected with the pressure loading device; the central axis of the upper mould, the lower mould and the pressure head are positioned on the same straight line. After the testing device and the method which are provided by the invention are adopted, the critical process conditions of a rheological instability phenomenon in a metal plastic deformation process can be determined under the actual working conditions, and the shear deformation of a plurality of deformation degrees can be obtained by means of a single test, so that the testing efficiency and the material utilization rate are improved.

Description

technical field [0001] The invention relates to the field of plastic processing, in particular to an industrial mould, a test device and a method for determining metal rheological instability conditions. Background technique [0002] The thermal deformation process of metal materials is a nonlinear and irreversible thermodynamic process away from equilibrium in the sense of thermodynamics. Using a series of steady-state physical metallurgical processes such as grain breaking and spheroidization, dynamic recovery and recrystallization, phase transformation and superplasticity that occur during the thermal deformation of metal materials, the precise structure and performance of metal materials and components can be realized. control. Local flow or local plastic instability is one of the basic phenomena in the forging process. The rheological instability phenomena (mainly including adiabatic shear bands, local plastic flow and cracking, etc.) during thermal deformation of met...

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Problems solved by technology

However, on the one hand, the above experimental devices are general-purpose test devices, which generally have special requirements for the sample size, and the sample size used is quite different from the actual working conditions, and the test results need to be further verified in the actual working conditions; On the other hand, plastic rheological instability of metal materials often occurs under complex stress state conditions during plastic processing. Conventional thermal compression tests, tensile tests, and torsion tests can only obtain simple stress states (such as uniaxial tension or Compression, single shear stress state), the SPHB test results only involve the analysis results of the unidirectional compressive stress state under specific assumptions

It can be seen that the existing related technologies cannot meet the needs of determining the plastic rheological instability conditions of metal materials in actual working conditions

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