TY - GEN

T1 - Investigation of the joining zone formation of impact extruded hybrid components by varied forming sequence and partial cooling

AU - Piwek, Armin

AU - Peddinghaus, Julius

AU - Uhe, Johanna

AU - Brunotte, Kai

AU - Behrens, Bernd Arno

N1 - Funding Information: The results presented in this paper were obtained within sub-project B03 of the Collaborative Research Centre 1153 “Process chain to produce hybrid high performance components with Tailored Forming” funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)-SFB 1153 TP B03-252662854. The authors thank the DFG for the financial support of this project and also the Institute of Materials Science for the SEM/EDX investigations.

PY - 2023/4/19

Y1 - 2023/4/19

N2 - Hybrid material concepts enable the combination of beneficial properties of different materials to extend the limited potential of monolithic components. When it comes to steel and aluminium, a wear-resistant and a lightweight metal are combined to produce a weight-reduced high-performance component with load-adapted areas. A method to create hybrid gear shafts is a novel approach called Tailored Forming. The process chain consists of joining e. g. by friction welding and subsequent impact extrusion under elevated temperature. Before forming, an axial temperature gradient is set in the serial arranged semi-finished products to adjust the different yield stresses of the dissimilar materials through induction heating of the steel part. The subsequent forming is intended to positively influence the joining zone thermo-mechanically and geometrically. However, prior work indicated a limitation of the influence on the joining zone in forward rod extrusion. Therefore, approaches are being researched that enable a stronger formation of the joining zone geometry to influence the resulting bond qualities through surface enlargement. A forward rod extrusion process of friction welded hybrid semi-finished products made of 20MnCr5 (AISI 5120H) combined with EN AW-6082 (AA6082) was carried out experimentally. Complementary to prior investigations, in which mainly the aluminium section was reduced through the die angle followed by the steel, the forming sequence of the materials was reversed to increase the joining zone surface with variation of the forming path. Additionally, a cooling of the aluminium side was realized through an immersion cooling to adjust maximum temperature gradients and further equalize the different yield stresses. Hardness tests, metallographic and SEM images of cross-sections were taken to evaluate the bond quality with regard to the temperature influence, joining zone formation, occurring defects and the resulting intermetallic compound (IMC). Impact extrusion with initially steel formed followed by aluminium resulted in a spherical formation of the joining zone and consequently in greater surface area, but also lead to partial defects in the IMC. The partial cooling of the aluminium allowed higher temperature gradients to be set, thus reducing defects through improved material flow in the joining zone.

AB - Hybrid material concepts enable the combination of beneficial properties of different materials to extend the limited potential of monolithic components. When it comes to steel and aluminium, a wear-resistant and a lightweight metal are combined to produce a weight-reduced high-performance component with load-adapted areas. A method to create hybrid gear shafts is a novel approach called Tailored Forming. The process chain consists of joining e. g. by friction welding and subsequent impact extrusion under elevated temperature. Before forming, an axial temperature gradient is set in the serial arranged semi-finished products to adjust the different yield stresses of the dissimilar materials through induction heating of the steel part. The subsequent forming is intended to positively influence the joining zone thermo-mechanically and geometrically. However, prior work indicated a limitation of the influence on the joining zone in forward rod extrusion. Therefore, approaches are being researched that enable a stronger formation of the joining zone geometry to influence the resulting bond qualities through surface enlargement. A forward rod extrusion process of friction welded hybrid semi-finished products made of 20MnCr5 (AISI 5120H) combined with EN AW-6082 (AA6082) was carried out experimentally. Complementary to prior investigations, in which mainly the aluminium section was reduced through the die angle followed by the steel, the forming sequence of the materials was reversed to increase the joining zone surface with variation of the forming path. Additionally, a cooling of the aluminium side was realized through an immersion cooling to adjust maximum temperature gradients and further equalize the different yield stresses. Hardness tests, metallographic and SEM images of cross-sections were taken to evaluate the bond quality with regard to the temperature influence, joining zone formation, occurring defects and the resulting intermetallic compound (IMC). Impact extrusion with initially steel formed followed by aluminium resulted in a spherical formation of the joining zone and consequently in greater surface area, but also lead to partial defects in the IMC. The partial cooling of the aluminium allowed higher temperature gradients to be set, thus reducing defects through improved material flow in the joining zone.

KW - Friction Welding

KW - Hot Forging

KW - Joining Zone

KW - Partial Cooling

KW - Tailored Forming

UR - http://www.scopus.com/inward/record.url?scp=85160245181&partnerID=8YFLogxK

U2 - 10.21741/9781644902479-64

DO - 10.21741/9781644902479-64

M3 - Conference contribution

AN - SCOPUS:85160245181

SN - 9781644902462

T3 - Materials Research Proceedings

SP - 591

EP - 600

BT - Material Forming

A2 - Madej, Lukasz

A2 - Sitko, Mateusz

A2 - Perzynsk, Konrad

T2 - 26th International ESAFORM Conference on Material Forming, ESAFORM 2023

Y2 - 19 April 2023 through 21 April 2023

ER -