TY - BOOK

T1 - Al-Mg-Si-Fe crossover alloys ¿ Control of microstructure and mechanical properties through Fe-rich primary phases

AU - Trink, Bernhard

N1 - no embargo

PY - 1800

Y1 - 1800

N2 - Over the past few decades, the rapid advancement of the traffic and transportation sector has led to significant changes in the global climate due to increasing CO2 emissions. Despite heightened political awareness and growing economic imperatives driving research and development in this sector, current technologies remain insufficient to fully address this challenge. An important way to increase energy savings and reduce harmful emissions is to optimize vehicle design, which is closely linked to the choice of materials. The use of lightweight materials such as aluminum alloys to replace high-density steel is a well-established strategy for reducing greenhouse gas emissions. Unfortunately, there are many challenges associated with the production of aluminum, such as the need for enormous amounts of electrical energy, which is again linked to greenhouse gas emissions, and the formation of tons of residue (red mud), which is a serious environmental concern. One way to address this problem is through recycling, which significantly reduces the amount of energy required by remelting scrap without producing red mud as a by-product. However, recycling of Al-alloys faces challenges due to the diverse composition of aluminum scrap. During the recycling process, impurities are introduced into the alloys, which can have a significant impact on their mechanical properties. Iron, considered a tramp element, is particularly undesirable in aluminum alloys because it is responsible for the deterioration of ductility and forming properties. In Al alloys it tends to form coarse and brittle intermetallic phases, which can cause internal damage during forming and lead to premature material failure. This research focuses on the development of a highly Fe-tolerant alloy concept based on Al-Mg-Si alloys capable of providing high ductility and formability. To avoid the negative effects of Fe and to effectively utilize the otherwise detrimental Fe-rich primary phases during microstructure evolution, a crossover approach is being pursued. Crossovers combine the beneficial material properties of existing aluminum alloys. By applying the crossover approach, the age-hardening capability of the 6xxx series and the microstructure control using primary phases in Fe-rich 8xxx (foil stock) alloys have been merged. By morphologically transforming the as-cast structure of Fe-rich primary phases into fine particles during thermomechanical treatment, significant grain refinement and uniform texture were achieved. In addition, the high density of ~1 µm particles contributes to good ductility, increased strength and work hardening through the formation of additional geometrically necessary dislocations (GNDs). The overall concept has been validated even under industrial production conditions, but further research is needed to fully exploit the potential of the introduced Al-Mg-Si-Fe crossover alloys.

AB - Over the past few decades, the rapid advancement of the traffic and transportation sector has led to significant changes in the global climate due to increasing CO2 emissions. Despite heightened political awareness and growing economic imperatives driving research and development in this sector, current technologies remain insufficient to fully address this challenge. An important way to increase energy savings and reduce harmful emissions is to optimize vehicle design, which is closely linked to the choice of materials. The use of lightweight materials such as aluminum alloys to replace high-density steel is a well-established strategy for reducing greenhouse gas emissions. Unfortunately, there are many challenges associated with the production of aluminum, such as the need for enormous amounts of electrical energy, which is again linked to greenhouse gas emissions, and the formation of tons of residue (red mud), which is a serious environmental concern. One way to address this problem is through recycling, which significantly reduces the amount of energy required by remelting scrap without producing red mud as a by-product. However, recycling of Al-alloys faces challenges due to the diverse composition of aluminum scrap. During the recycling process, impurities are introduced into the alloys, which can have a significant impact on their mechanical properties. Iron, considered a tramp element, is particularly undesirable in aluminum alloys because it is responsible for the deterioration of ductility and forming properties. In Al alloys it tends to form coarse and brittle intermetallic phases, which can cause internal damage during forming and lead to premature material failure. This research focuses on the development of a highly Fe-tolerant alloy concept based on Al-Mg-Si alloys capable of providing high ductility and formability. To avoid the negative effects of Fe and to effectively utilize the otherwise detrimental Fe-rich primary phases during microstructure evolution, a crossover approach is being pursued. Crossovers combine the beneficial material properties of existing aluminum alloys. By applying the crossover approach, the age-hardening capability of the 6xxx series and the microstructure control using primary phases in Fe-rich 8xxx (foil stock) alloys have been merged. By morphologically transforming the as-cast structure of Fe-rich primary phases into fine particles during thermomechanical treatment, significant grain refinement and uniform texture were achieved. In addition, the high density of ~1 µm particles contributes to good ductility, increased strength and work hardening through the formation of additional geometrically necessary dislocations (GNDs). The overall concept has been validated even under industrial production conditions, but further research is needed to fully exploit the potential of the introduced Al-Mg-Si-Fe crossover alloys.

KW - aluminum alloys

KW - crossover alloys

KW - Fe-rich intermetallic phases

KW - grain refining

KW - particle stimulated nucleation

KW - mechanical properties

KW - microstructure analysis

KW - Aluminiumlegierungen

KW - Crossover-Legierungen

KW - Fe-reiche intermetallische Phasen

KW - Kornfeinung

KW - partikelstimulierte Keimbildung

KW - mechanische Eigenschaften

KW - Mikrostrukturanalyse

M3 - Doctoral Thesis

ER -