摘要
随着装药战斗部对材料性能要求的不断提升,阐明纳米粉末在冲击载荷下的微观组织演变过程成为优化毁伤元材料的关键问题。采用分子动力学方法,对比研究了典型Al基纳米粉末Al-Fe-Ni和Al-Fe的冲击波传播特性、相变行为及位错演变规律,揭示了冲击速度和Ni元素引入对Al基纳米颗粒微观组织演变的作用机制。结果表明:提高冲击速度会显著增强材料的热力响应特征,并促进相变;当冲击速度为0.6 km/s时,Fe和Ni颗粒未发生显著变形;当冲击速度升高至1.5 km/s时,压力超过35 GPa,温度超过6000 K,Al颗粒熔化,Fe和Ni颗粒深度融合,热力耦合作用导致大量无序结构产生。冲击速度不会影响位错空间分布,但可显著调控位错密度;Ni元素的引入可增强材料的热力响应,改变体心立方相的演变路径,提升密排六方结构占比,同时提高位错密度,调控位错反应时机,促进不可动位错、位错钉扎及位错环结构形成,影响位错的时序演化和空间分布特征。研究结果可为优化毁伤元材料的制备工艺及应用提供依据。
With the continuous improvement of the material performance requirements of the charged warheads,elucidating the microstructural evolution of nano-powders under shock loading becomes critical for optimizing damage-element materials.In this study,molecular dynamics simulations were employed to comparatively investigate the shock wave propagation characteristics,phase transition behavior,and dislocation evolution of typical Al-based nanostructured powders Al-Fe-Ni and Al-Fe.This study reveals the mechanisms of impact velocity and Ni element on the evolution of Al-based nanoparticles.The results indicate that increasing shock velocity significantly enhances the thermodynamic response of the materials and promotes phase transition.Fe and Ni particles exhibit minimal deformation at an impact velocity of 0.6 km/s.When the velocity was increased to 1.5 km/s,the pressure exceeds 35 GPa and the temperature surpasses 6000 K,resulting in the melting of Al particles and deep fusion of Fe and Ni particles.The thermodynamic coupling effects lead to the formation of a large number of other structures.Furthermore,shock velocity does not affect the spatial distribution of dislocations but significantly regulates dislocation density.The introduction of the Ni element enhances the thermodynamic response of the material,alters the evolution pathway of the body-centered cubic phase and increases the proportion of hexagonal close-packed structures.Moreover,Ni element introduction raises the dislocation density,adjusts the timing of dislocation reactions,and promotes the formation of sessile dislocations,dislocation pinning,and dislocation loop structures,thereby influencing the temporal evolution and spatial characteristics of dislocations.These findings provide a theoretical basis for optimizing the processing of damage-element materials and their application.
作者
安豪
李强
张正涛
王启云
丛兴龙
樊壮
AN Hao;LI Qiang;ZHANG Zhengtao;WANG Qiyun;CONG Xinglong;FAN Zhuang(School of Mechanical and Electrical Engineering,North University of China,Taiyuan 030051,Shanxi,China;No.208 Research Institute of China Ordnance Industries,Beijing 102202,China)
出处
《高压物理学报》
北大核心
2025年第8期1-11,共11页
Chinese Journal of High Pressure Physics
基金
基础加强计划技术领域基金(2023-JCJQ-JJ-0264)
山西省自然科学基金(20210302124196,202203021211097)
中北大学重点实验室开放研究基金(DXMBJJ2023-04)
中北大学研究生科技立项课题(20242004)。
关键词
冲击载荷
Al基纳米粉末
微观组织演变
分子动力学
位错
impact loading
Al-based nano-powder
microstructural evolution
molecular dynamics
dislocation
