应变速率对藕状多孔镁垂直于气孔方向压缩变形行为与力学性能的影响

发布时间：2018-03-13 00:04

本文选题：藕状多孔镁　切入点：应变速率　出处：《中国有色金属学报》2016年12期 　论文类型：期刊论文

【摘要】：利用定向凝固法制备藕状多孔镁,采用GLEEBLE~(-1)500型材料模拟实验机和分离式霍普金森压杆(SHPB)装置,在以1×10~(-3)~1650 s~(-1)的应变速率范围内沿垂直于气孔方向进行压缩实验,研究应变速率对藕状多孔镁压缩变形行为和力学性能的影响。结果表明:当垂直于气孔方向压缩时,藕状多孔镁的应力-应变曲线分为应力线性增加的弹性阶段、应力缓慢增加的平台阶段和应力急剧增加的密实化阶段,应力随应变的增加持续增大,无应力峰值的出现。而当垂直于气孔方向压缩时,应变速率对藕状多孔镁的变形行为影响显著,在应变速率ε60 s~(-1)条件下,主要变形方式为气孔先发生椭圆化变形,然后部分气孔的孔壁率先向气孔内发生弯月形塌陷并形成垂直于压缩方向的先变形带,随后变形带不断产生,从而逐步实现密实化;而较高应变速率(ε=450~1650 s~(-1))下的变形方式虽然气孔也是先后发生椭圆化、孔壁向气孔内的弯曲塌陷等变形并形成先变形带,但先变形带沿试样对角线方向率先形成,并随压缩进行不断向与对角线垂直的方向扩展。应变速率对藕状多孔镁的力学性能有较明显的影响,其影响机制主要是由于不同应变速率时气孔的变形方式发生了变化。
[Abstract]:The lotus root porous magnesium was prepared by directional solidification method. The compression experiments were carried out at the strain rate range of 1 脳 10 ~ (-3) ~ (3) C ~ (-1) ~ (-1), perpendicular to the pore direction, using a GLEEBLE~(-1)500 material simulation machine and a split Hopkinson pressure bar (SHPBB) apparatus. The effect of strain rate on compressive deformation behavior and mechanical properties of lotus root porous magnesium was studied. The results show that the stress-strain curve of lotus root porous magnesium can be divided into elastic phase with linear increase of stress when compressed perpendicular to the pore direction. When the stress increases slowly in the platform stage and in the dense stage in which the stress increases sharply, the stress increases continuously with the increase of strain, and the peak stress does not appear. However, when the stress is compressed perpendicular to the stomatal direction, The strain rate has a significant effect on the deformation behavior of lotus root porous magnesium. Under the strain rate 蔚 60 s-1), the main deformation mode is the elliptical deformation of pores. Then the hole wall of part of the pore first collapses into the stomata and forms the first deformation zone perpendicular to the compression direction, and then the deformation zone is produced continuously, so that the compaction is realized step by step. However, the deformation mode at higher strain rate (蔚 _ (450) ~ (1650) ~ (-1)) is elliptical successively, and the deformation zone is formed first along the diagonal direction of the specimen, such as bending and collapsing of the pore wall to the pore, but the first deformation zone is formed along the diagonal direction of the specimen, and the first deformation zone is formed along the diagonal direction of the specimen, and the first deformation zone is formed at the same time. The strain rate has obvious influence on the mechanical properties of lotus root porous magnesium, and the mechanism is mainly due to the change of the deformation mode of pores at different strain rates.
【作者单位】：北京科技大学新材料技术研究院;
【基金】：国家自然科学基金资助项目(50904004)~~
【分类号】：TG146.22;TB383.4

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