A Novel Severe Plastic Deformation Method for Manufacturing Al/Mg bimetallic Tube

A new severe plastic deformation for manufacturing Al/Mg bimetallic tube called TES (Tube Extrusion Shearing) process, which combines direct extrusion with two step shearing, is developed to Al/Mg bimetallic tube. To explore the deformation mechanism for Al/Mg bimetallic tube during TES process, both experiments and numerical simulations have been carried out. The stroke loads during TES process of Al/Mg bimetallic tubes have been simulated by establishing three-dimensional finite element model. Experiments show that by use of TES process the microstructures can be refined to 50% of the original grain size and with more uniform grain distribution. TES process could improve hardness obviously by comparing which fabricated by direct extrusion. Numerical results indicate TES increases the cumulative strains effectively by direct extrusion and additional shearing. The micro-structures and mechanical properties of the bonded layer were analyzed, The results showed that under the extrusion temperature of 420℃, the bonding layer of the sample obtained by extrusion shearing had no hole defects, and the thickness was about 22um, among which the stable layer was about 11um.The average hardness of the bonding layer is 221HV.

The Influence of the Components of the Bimetallic Tubes for the Way of Deforming in the Hollow Drawing Process

Processes for producing bimetallic tubes can be divided for: producing the bimetallic tubes in the cold process, with preheating or with the heat treatment after each pull. First method relates to the metal with high ductility (copper, copper alloys, aluminum, aluminum alloys, zinc, etc.), second to the metals or bi-metal components, in one of which has significantly different plastic properties from the second for example: low-carbon steel, high alloy steel, etc. One of the methods for the production of bimetallic tubes is hollow cold drawing process. In this process the wall thickness is changed, which means the wall becomes thicker, the wall becomes thinner or remains unchanged. The aim of the research was to determine the effect of the influence of the share of components of bimetallic cooper tube species M1E, and the copper tube - species M63 in the arrangement M1E - M63 and M63 - M1E in the tubes hollow drawing process for the distribution and size of deformation of the individual layers. The research program included:- production of the bimetallic tubes by hollow drawing with a different percentage of the cross-section components and with a variable arrangement of layers,- determination of the size and distribution of true strain of the individual layers on the cross-section of bimetallic tube,- determination of replacement/equivalent strain for the deformable wall of the bimetallic tube,- evaluation of the usability of the graph of changes in thickness of the tube wall in the hollow drawing process for the drawing process of the bimetallic tubes.