Deformation and densification behavior of discrete media filled thin-walled tubes during forward extrusion
(1. College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China;
2. Northwest Institute for Nonferrous Metal Research, Xi’an 710016, China)
2. Northwest Institute for Nonferrous Metal Research, Xi’an 710016, China)
Abstract: 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.
Key words: tube; forward extrusion; powder; deformation behavior; densification