Deformation and densification behavior of discrete media filled thin-walled tubes during forward extrusion

离散介质充填薄壁管正挤压过程的变形与致密化行为（英文）

Discrete media filled thin-walled hollow profiles are frequently used as integer structures for special purpose, e.g., in certain materials processing or architectural components. To understand the deformation of such composite structures which is a complicate mechanics process, involving coupled elastic-plastic deformation of dense metal, compaction of particle and interaction between the filler and the wall, the forward extrusion of Al 6061 tubes filled with various particles was studied. The analysis regarding internal volume variation of round tubes during forward extrusion indicates that with the diameter reduction the volume of tubes decreases commonly. The cavity shrinkage brings about triaxial pressure on the filler, resulted in compaction and densification of it. Loose powders filling leads to higher extrusion load. Due to dissimilar migration behaviors of the particles, the load?stroke curves of the tubes filled with fine powders and coarse balls are quite different. Small Lankford value of the tube wall material leads to higher hydrostatic pressure of the filler and then more powders are compacted.

离散介质填充的中空薄壁型材常常作为整体结构用于一些特殊场合,如某些材料成型过程或建筑构件。这类复合结构的变形涉及致密金属的弹塑性耦合变形、松散颗粒压实以及管壁与填充物之间的相互作用。为认识其复杂力学行为,研究了填充不同粒度和材质的两种颗粒的Al 6061管正挤压过程。对圆管坯内腔体积变化的分析表明,随着正挤压时外径缩小,内腔容积通常减小,从而给填充物带来三轴压力并导致其致密化。填充使得挤压载荷增加;由于细粉和钢丸具有不同迁移与重排方式,二者的挤压力-行程曲线呈现不同形态。此外,较小的管材r值(Lankford值)使得填充介质静水压力增加并提高其致密化程度。