TY - JOUR

T1 - Thermal Analysis and Production of As-Cast Al 7075/6060 Bilayer Billets

AU - Greß, Thomas

AU - Mittler, Tim

AU - Schmid, Simon

AU - Chen, Hui

AU - Ben Khalifa, Noomane

AU - Volk, Wolfram

N1 - The “Determination and control of bonding properties in aluminum composites in the combination of compound casting and forming” project is funded by the German Research Foundation (DFG) under grant VO-1487/25-1. The authors acknowledge the financial support from the DFG. Furthermore, the authors would like to express their gratitude to the Fraunhofer Research Institute for Casting, Composite and Processing Technology IGCV for their assistance in the measurement of thermophysical data.

PY - 2019/10/1

Y1 - 2019/10/1

N2 - Load-adjusted, weight-optimized components can be fabricated by following a multi-material approach. Integrating the respective advantages of strength and corrosion resistance of Al 7075 and Al 6060 into a single structural component leads to a complex property profile. Compound casting offers a high potential in terms of process chain shortening, material efficiency and bonding quality. The present paper focuses on the production of aluminum bilayer billets by multi-step, discontinuous compound casting. Process conditions influencing the formation of a cohesive bond at the interface are investigated. A fundamental thermal analysis is conducted in order to fully characterize the casting alloys. A process window for metallurgical bonding of Al 7075 and Al 6060 can be defined using a combined approach of process parameters and thermophysical data. The primary bonding mechanism is found to be the epitaxial solidification which occurs through remelting and recrystallization of the substrate alloy. Here the dendrite coherence point constitutes a critical level of the near-interface substrate temperature in terms of forming a solid solution. Epitaxy, phase composition and intermetallic diffusion processes are analyzed using SEM–EDS.

AB - Load-adjusted, weight-optimized components can be fabricated by following a multi-material approach. Integrating the respective advantages of strength and corrosion resistance of Al 7075 and Al 6060 into a single structural component leads to a complex property profile. Compound casting offers a high potential in terms of process chain shortening, material efficiency and bonding quality. The present paper focuses on the production of aluminum bilayer billets by multi-step, discontinuous compound casting. Process conditions influencing the formation of a cohesive bond at the interface are investigated. A fundamental thermal analysis is conducted in order to fully characterize the casting alloys. A process window for metallurgical bonding of Al 7075 and Al 6060 can be defined using a combined approach of process parameters and thermophysical data. The primary bonding mechanism is found to be the epitaxial solidification which occurs through remelting and recrystallization of the substrate alloy. Here the dendrite coherence point constitutes a critical level of the near-interface substrate temperature in terms of forming a solid solution. Epitaxy, phase composition and intermetallic diffusion processes are analyzed using SEM–EDS.

KW - Engineering

KW - thermal analysis

KW - aluminum bimetal

KW - dendrite coherence point

KW - compound casting

KW - bilayer billet

KW - epitaxy

UR - http://www.scopus.com/inward/record.url?scp=85062146302&partnerID=8YFLogxK

U2 - 10.1007/s40962-018-0282-8

DO - 10.1007/s40962-018-0282-8

M3 - Journal articles

VL - 13

SP - 817

EP - 829

JO - International Journal of Metalcasting

JF - International Journal of Metalcasting

SN - 1939-5981

IS - 4

ER -