Abstract
The valence electron structure (VES) parameters affecting adiabatic shearing failure under high speed impact load using split Hopkinson pressure bar (SHPB) were studied by empirical electron theory (EET) of solids and molecules. There is a problem of multiple solutions about VES parameters in EET. The statistics values of VES parameters related to adiabatic shearing sensitivity were calculated to substitute for the most probable value among the multiple solutions according to the view that the microstate statistics values can reflect the macro physical quantity. The research shows that the adiabatic shearing sensitivity is growing with the rise of the statistics value of bond energy of the strongest covalent bond, and is decreasing with the rise of the statistics value of the lattice electron number. The statistics value of bond energy of the strongest covalent bond in aluminum bronze (QAl9-4) is larger than that in pure copper, and the statistics value of the lattice electron number in QAl9-4 is smaller than that in pure copper. Therefore, QAl9-4 is prone to adiabatic shearing failure, and the grains were only elongated due to the large deformation for pure copper without any adiabatic shear band (ASB). It is of great significance for the selection and design of material with different adiabatic shearing sensitivity to research the effect of alloy elements on adiabatic shearing sensitivity from the electronic structure perspective.
Highlights
The process of high speed deformation of material is often accompanied with different internal micro damage evolution that eventually leads to the failure of material
Serrated chip caused by adiabatic shear band (ASB), which affects the surface quality and tool wear and causes a high frequency change of cutting force,[3] often occurs in the process of high speed cutting.[4,5,6,7,8]
The research about adiabatic shearing sensitivity mainly focused on the phenomenological explanation and macroscopic understanding by the test of microstructure and properties. It is of great significance for the selection and design of material with different adiabatic shearing sensitivity, or the avoidance of adiabatic shear phenomenon to research the effect of alloy elements on adiabatic shearing sensitivity from the electronic structure perspective because the material macro material performance stems mainly from its micro-electronic structure
Summary
The process of high speed deformation of material is often accompanied with different internal micro damage evolution that eventually leads to the failure of material. Cheng[17] proved that the discriminant in EET is inevitable result of first principle It provides a simple and effective method for studying the essential characteristics of materials on the electronic structure level. Researchers have successively studied how to describe the physical performance of material,[18,19] including melting point, electrical conductivity, strength, magnetic property, etc.[20,21,22,23] using the VES parameters in EET since the theory was proposed. The damage characteristics of pure copper and aluminum bronze (QAl9-4) was analyzed by SHPB test and the VES parameters affecting adiabatic shearing sensitivity were studied on the electronic structure level using EET. The research result can provided the basis for choosing and designing the materials having different adiabatic shearing sensitivity
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