Charakterisierung der Luftfahrtlegierung AA7050 zur Optimierung des industriellen Warmwalzens

Translated title of the contribution: Characterization of AA7050 for aerospace applications to optimize the hot rolling process

Andreas Martin Weber

Research output: ThesisMaster's Thesis

Abstract

AMAG rolling GmbH produces high quality aluminium products for the aviation industry, for example the AA7050. Since the requirements on strength and fracture toughness are constantly increasing, the current process management is not satisfying. To optimize the characteristics of micro structure and to enhance the mechanical properties it is necessary to reduce the recrystallized structure fraction in the rolled product. The homogenization conditions and the hot rolling process are assumed to have the greatest influence. The main focus is set on the homogenization time, the following cooling conditions and the variable heating before hot forming. Moreover, the influence of the deformation energy is tested by varying pass reduction. These experiments were accomplished with the Servotest Thermomechanical Treatment Simulator of the chair of metalforming. It was shown, that three criteria strongly influence occurrence of the recrystallization: A long homogenization time leads to the formation of coarse secondary phases (>5 m), a lower deformation rate at high rolling temperature induces lower deformation energy and the formation of Al3Zr particles hinders the recrystallization. Tests with a water quenched structure and those which where direct deformed after homogenization were showing the best results. Furthermore, the influence of cracking during hot deformation, it est crocodiling, was investigated by wedge tests at different rolling temperatures. The global temperatures limit was found at 460°C. At this temperature first locally melted material can lead to crack initiation and fracture. At least hot flow curves and thermo physical data were documented to characterize the material.
Translated title of the contributionCharacterization of AA7050 for aerospace applications to optimize the hot rolling process
Original languageGerman
QualificationDipl.-Ing.
Supervisors/Advisors
  • Sommitsch, Christof, Supervisor (internal)
  • Sherstnev, Pavel, Co-Supervisor (internal)
Award date19 Dec 2008
Publication statusPublished - 2008

Bibliographical note

embargoed until null

Keywords

  • Aluminium alloy AA7050 Fracture Toughness

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