Papers by Keyword: Bar Extrusion

Abstract: The integration of functions in lightweight structures features great potential for future applications in diagnosis and control. The combination of shape memory wires or ribbons made of NiTi embedded in aluminium and manufactured by composite extrusion offers the possibility to produce a composite actuator material in a single production step. The extrusion process allows a wide range of shapes and provides higher versatility than actuators made of bi-metals. The transformation temperature of NiTi varies depending on the composition of the alloy, between -100 °C and 100 °C. However, NiTi can also transform stress-induced. In the designated application, a force is applied via the interface onto the matrix material to deform it. Due to the resulting stress, the transformation temperature rises to temperatures higher than those of the unloaded material. Furthermore the production of composite extrusions leads to a significant heat input on the shape memory alloys followed by another increase of the transformation temperature.Therefore it is essential to reproduce the heat treatment and the stress-induced transformation to predict the transformation temperature in the resulting composite influenced by the interface. For that purpose, the wire gets annealed in a furnace with different durations at a temperature similar to that of the bar extrusion process. After this, the transformation temperatures can be observed at various stresses to evaluate their applicability for aluminium composite actuators.

Abstract: This paper presents and discusses the latest achievements in the manufacture of threedimensionally curved aluminum profiles using an integrated bar extrusion process. While the conventional process chain lacks applicability and quality especially in low volume production, the new technology is promising, but still needs research to understand the correlation between the product to be manufactured and the contour accuracy to be achieved. This paper shows first results on the manufacture using a robot-guided second guiding tool and direct air quenching. The results will have an impact on further processing steps