Quasi-in-situ experimental method of dynamic compression deformation and failure behavior of metal material

Abstract

The invention belongs to a quasi-in-situ experimental method of dynamic compression deformation and failure behavior of a metal material in the field of dynamic mechanics experiments of materials. Theexperimental method comprises specific steps as follows: (1) preparing a D column type sample, polishing the side surface, and observing the structure morphology and grain orientation of the sample before deformation; (2) performing single-axial dynamic compression loading on the sample; (3) performing quasi-in-situ observation on the structure morphology and grain orientation of the same area ofthe compressed sample; (4) performing single-axial dynamic compression on the sample at the same strain rate and deformation temperature to increase the total strain; (5) repeating steps (3) and (4)until the sample is damaged, further analyzing observed structure morphology and grain orientation information, and restoring the change of the structure in the dynamic compression deformation and failure process. The dynamic compression deformation and failure behavior of the metal material at the strain rate of 10<3> s<-1>-10<4>s<-1> and at the deformation temperature of 20 DEG C-400 DEG C can be disclosed with the method.

Description

technical field [0001] The invention belongs to the field of material dynamic mechanics experiments, in particular to a quasi-in-situ experimental method for dynamic compression deformation and failure behavior of metal materials. Background technique [0002] The dynamic deformation and failure behavior of materials refers to the mechanical behavior of materials under high strain rate (higher than 5 / s), involving many civil and military fields such as explosive forming, impact synthesis, high-speed penetration and impact protection. Studies have confirmed that there is a clear difference between the dynamic and quasi-static mechanical behavior of materials: under quasi-static conditions, the strain rate at which the material deforms is low, and each unit inside the material can be regarded as at any point in time. The state of stress balance and heat balance; under dynamic conditions, the strain rate of deformation is relatively high, and the inside of the material deviates...

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Problems solved by technology

However, the dynamic deformation and failure process of the material is extremely short (less than 100μs), and there is no effective experimental method to record the change process of the microstructure at this moment in time series.

Although, the strain “freezing” of the material can be achieved by using the Hopkinson system and the limit device, even if the material stops the deformation process when the dynamic deformation reaches a certain strain, however, due to the limitation of the shape of the sample (the shape characteristics of the previous sample: vertical The section in the direction of the loading axis is a circular surface or an annular surface), and the side of the sample cannot be polished. It is necessary to cut the sample along the axial direction and perform surface treatment to obtain tissue information. Therefore, the sample after observation cannot be restored. Some shapes cannot be loaded again under the same conditions, and the continuous deformation process of the tissue in the same area cannot be obtained, that is, it is not an "in situ" continuous observation analysis

[0004] At present, the research on the dynamic deformation and failure behavior of materials still adopts the "final state" observation method, that is, only the microstructure of the material after deformation or failure is observed, and then the change process is reversed through the observed phenomenon, which leads to dynamic deformation. Information such as the activation sequence of the slip system and the twin system, the nucleation position and the propagation path of the crack cannot be known until the failure process, and it is impossible to grasp the whole process of dynamic deformation and microstructure change during the failure process.

To understand the dynamic deformation and failure behavior of materials in depth, it is necessary to solve the problem that the dynamic deformation and failure process of materials cannot be continuously observed

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