Damage Behaviors Of AZ31Magnesium Alloy And Zirconium702Induced By Hypervelocity Impact

In this paper, after a series of impact tests with the high-velocity from0.7km/sto1.1km/s carried out by using a powder gun, the damage behaviors of the AZ31magnesium alloy and Zr702were studied by means of optical microscope (O M),scanning electron microscope (SEM) and transmission electron microscope (TEM).With employment of the ANSYS AUTODYN software, the mechanical damageprocess of AZ31magnesium alloy impacted by high-velocity or hypervelocity wassuccessfully numerically simulated.The impact experiment results show that under the same impact condition, asthe AZ31alloy or Zr702target not penetrated, with increasing target thickness, thediameter of the impacted crater increases while the depth and volume decreases, andfinally to a stable value, As increasing the target thickness, the energy consumptionfor crater formation would be reduced, and the penetration ability of projectile alongdepth of crater would decrease while the ability along radial direction increases. Thestrength variation between the Al or steel projectile and AZ31alloy or Zr702targetcould influence the process of crater formation, if the strength of projectile waslower than that of target, the crater would be hard to form and lead to smaller crat erbecause more energy was consummated during impacting process. It is suggestedthat the material parameter σs,, H, ρ, Tm, can be used to evaluate the impactresistance of HCP metallic materials.Under the impact conditions applied in this study, a grou p of adiabatic shearbands (ASBs) near the impacted crater, varying in morphology due to the position,in the AZ31alloy target can be found. But a few of ABSs which spreadsindependently in Zr702target can be seen, It implies that the heat softening woul dmore easy to occur in AZ31alloy and induce plasticity buckling during thehigh-velocity impact process. Impacted at a velocity of1.1km/s, fine equiaxedgrains produced by dynamic recrystallization in the ASBs of AZ31alloy could befound. These equiaxed grains were transferred from the sub-structures produced bypile-up, slip and formation of a large amount of dislocations during impactingprocess. It is also found that at the same impact velocity, as the thickness of AZ31alloy or Zr702targets larger than the critical thickness for penetration, the amountand distribution density of ASBs increase firstly, and then decrease with increasingthe target thickness. For thinner target, the development of ASBs was restricted bythe formation of larger amount of cracks. And for thick target, formation of ASBswas restricted by the energy consumption during impact process. The mechanical damage process of AZ31magnesium alloy under high-velocityand hypervelocity impact has been successfully simulated by using ANSYSAUTODYN software. The simulation results show that, within the velocity of10km/s, the ratio of the depth and diameter of the crater impacted by GCr15steelprojectile is found greater than1, and with increasing impact velocity, the ratiodecreases and approach to1. The ratio of the depth and diameter of the craterimpacted by Al projectile is less than1, and with increasing impact velocity, theratio increases to0.7and become stable as the velocity up to4km/s.