Muskeri Saideep, Gwalani Bharat, Jha Shristy, Yu Anqi, Jannotti Philip A, Haridas Ravi Sankar, Schuster Brian E, Lloyd Jeffrey T, Mishra Rajiv S, Mukherjee Sundeep
Department of Materials Science and Engineering, University of North Texas, Denton, TX, 76203, USA.
Advanced Materials and Manufacturing Processes Institute, University of North Texas, Denton, TX, 76207, USA.
Sci Rep. 2021 Nov 22;11(1):22715. doi: 10.1038/s41598-021-02209-y.
Multi-principal element alloys represent a new paradigm in structural alloy design with superior mechanical properties and promising ballistic performance. Here, the mechanical response of AlCoCrFeNi alloy, with unique bimodal microstructure, was evaluated at quasistatic, dynamic, and ballistic strain rates. The microstructure after quasistatic deformation was dominated by highly deformed grains. High density of deformation bands was observed at dynamic strain rates but there was no indication of adiabatic shear bands, cracks, or twinning. The ballistic response was evaluated by impacting a 12 mm thick plate with 6.35 mm WC projectiles at velocities ranging from 1066 to 1465 m/s. The deformed microstructure after ballistic impact was dominated by adiabatic shear bands, shear band induced cracks, microbands, and dynamic recrystallization. The superior ballistic response of this alloy compared with similar AlCoCrFeNi alloys was attributed to its bimodal microstructure, nano-scale L1 precipitation, and grain boundary B2 precipitates. Deformation mechanisms at quasistatic and dynamic strain rates were primarily characterized by extensive dislocation slip and low density of stacking faults. Deformation mechanisms at ballistic strain rates were characterized by grain rotation, disordering of the L1 phase, and high density of stacking faults.
多主元合金代表了结构合金设计的一种新范式，具有优异的力学性能和良好的弹道性能。在此，对具有独特双峰微观结构的AlCoCrFeNi合金在准静态、动态和弹道应变率下的力学响应进行了评估。准静态变形后的微观结构以高度变形的晶粒为主。在动态应变率下观察到高密度的变形带，但没有绝热剪切带、裂纹或孪晶的迹象。通过用6.35毫米WC弹丸以1066至1465米/秒的速度冲击一块12毫米厚的板材来评估弹道响应。弹道冲击后的变形微观结构以绝热剪切带、剪切带诱发裂纹、微带和动态再结晶为主。与类似的AlCoCrFeNi合金相比，这种合金优异的弹道响应归因于其双峰微观结构、纳米级L1析出物和晶界B2析出物。准静态和动态应变率下的变形机制主要以广泛的位错滑移和低密度的堆垛层错为特征。弹道应变率下的变形机制以晶粒旋转、L1相无序化和高密度的堆垛层错为特征。
