Copper Based Metal Liner Material Under High Strain Rate Study On Dynamic Mechanical Properties

In order to improve the damage power of armor-breaking projectiles,a large number of studies have been carried out on the application of new high-energy explosives in armor-breaking projectiles at home and abroad.Under the condition of high explosive charge,it is difficult to crush the liner and form jet when using the new liner material.In order to seek the liner material matched with high-energy explosives,Cu-Zn alloy and Cu-Mn alloy were selected and prepared.In order to design the charge structure matching with high-energy charge,it is necessary to study the mechanical properties of two copper alloys.Therefore,it is of great significance to study the dynamic mechanical properties of metal materials at high strain rates.In this paper,the mechanical properties of Cu-Zn and Cu-Mn alloys were analyzed according to quasi-static tensile,dynamic compression and dynamic shear tests.Through the error analysis of the test data obtained from different cap-shaped structures,the cap-shaped sample structure suitable for alloy materials is selected.Combined with the test data of mechanical properties,the strain rate strengthening coefficient was corrected,and the J-C dynamic constitutive mechanical parameters of alloy materials were fitted.The conclusions of this study are as follows:（1）The dynamic shear mechanical properties of Cu-Zn alloy and Cu-Mn alloy with different hat shaped were studied,and it is considered that the shear mechanical properties obtained with different hat shaped were quite different.Based on the analysis of strain rate sensitivity,it is found that the hat shaped specimen with the inner diameter ratio greater than 1are suitable for studying the dynamic mechanical properties of Cu-Zn and Cu-Mn alloys at high strain rates.（2）To ensure the integrity of mechanical properties research,the quasi-static and compressive mechanical properties of Cu-Zn and Cu-Mn alloys were studied.The results show that the mechanical properties of Cu-Mn alloy are better than those of Cu-Zn alloy.Through the analysis of dynamic compression test data,it is found that the strain rate softening phenomenon occurs in the stress-strain curve after the strain rate reaches the critical value,which is caused by the thermal softening effect,and the fracture strain increases with the increase of strain rate,indicating that Cu-Zn and Cu-Mn alloys have strain rate plasticizing effect.（3）The strain rate sensitivity of alloy materials was studied based on the mechanical property test data.According to the stress-strain rate scatter plot,it was found that the flow stress of Cu-Zn alloy increased with the increase of strain rate.The strain rate sensitivity of Cu-Mn alloy is low,indicating that Cu-Zn alloy has positive strain rate sensitivity,while Cu-Mn alloy has no obvious strain rate sensitivity.（4）In order to obtain the strain rate hardening coefficient at high strain rate,the strain rate hardening effect parameters were modified by Cowper-Symonds formula.The C₁ and C₂ values of Cu-Zn alloy were 2.46×10^-3 and 0.65,respectively.The strain rate strengthening parameters obtained by linear fitting of Cu-Mn alloy can accurately reflect the dynamic mechanical properties of the alloy at higher strain rates,and the C value is 0.021.The research results of this paper provide theoretical guidance and technical support for the selection of liner materials and structure optimization under the condition of high-energy explosive charge.