In this article, mechanical properties and ballistic performance of friction-stir- welded magnesium alloy (AZ31B) have been studied using numerical and experimental techniques. Tensile properties and microhardness of the weldment were determined as per the ASTM E08 and E384-05 standards. Tensile properties and microhardness of the weldments are observed to be lesser than the Base Metal (BM). Microstructure analysis of the Nugget Zone (NZ) showed discontinuous dendritic structure and less β-Mg₁₇Al₁₂ phase. The ballistic impact performance of Mg weldment and BM were analysed using numerical code and validated by ballistic experiments. Armour-Piercing Projectile (APP) of 7.62 mm with an initial projectile velocity of 456 ± 10 m/s was considered for both the studies. Primarily, numerical analysis was performed using ABAQUS 6.14 finite element software with Johnson-Cook failure criterion. For each ballistic impact test, the residual velocity of the projectile was measured. To validate the numerical observations, experimental ballistic test was conducted as per the National Institute of Justice (NIJ) standard. The experimental residual velocity of each target was estimated using Recht-Ipson analytical model. It was found that the ballistic performance of weldments is inferior (26%) when compared to BM target. A good correlation of residual velocity was noted for the numerical and experimental methods. Scanning Electron Microscope (SEM) analysis of the FSW fracture surface showed the adiabatic shear bands.

中文翻译：

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焊接镁（AZ31B）板的数值和实验弹道性能

在本文中，已经使用数值和实验技术研究了搅拌摩擦焊接镁合金（AZ31B）的力学性能和弹道性能。焊件的拉伸性能和显微硬度根据ASTM E08和E384-05标准确定。观察到焊件的拉伸性能和显微硬度低于母材（BM）。熔核区（NZ）的微观结构分析显示不连续的树枝状结构和更少的β-Mg系₁₇的Al ₁₂相。利用数值分析方法分析了镁焊件和镁合金的弹道冲击性能，并通过弹道实验对其进行了验证。两项研究均考虑了7.62 mm的装甲穿甲弹（APP），初始弹丸速度为456±10 m / s。首先，使用具有Johnson-Cook破坏准则的ABAQUS 6.14有限元软件进行了数值分析。对于每个弹道冲击试验，都测量了弹丸的残余速度。为了验证数值观察结果，根据美国国家司法学院（NIJ）标准进行了实验性防弹测试。使用Recht-Ipson分析模型估算每个目标的实验残余速度。发现与BM目标相比，焊件的弹道性能较差（26％）。数值和实验方法都表明残余速度具有良好的相关性。FSW断裂表面的扫描电子显微镜（SEM）分析显示了绝热剪切带。