Investigation of the Interface Reaction of Al and Binary Al-alloys on Mild Steel Substrates for Al Compound Casting

Werner Fragner

Research output: ThesisDoctoral Thesis

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Abstract

The requirements of politics and manufacturers for weight-saving and low-cost production of prospective of components for future transport vehicles are getting more and more severe. For this reason the concept of multi-material mix is of increasing importance. In this context aluminum-iron compounds produced by means of compound casting (steel insert recast with aluminum) are considered to be of particular importance due to their high potential for cost savings and integration of function. An essential and critical aspect of such compound castings is the formation of intermetallic phases (IMP) at the Al-Fe interface. Both the nature and the kinetics of potential IMPs are not well understood and require a systematic investigation. This work deals with the formation of intermetallic phases at the interface of steel to aluminum and aluminum alloys. Aim of this thesis is to determine the emerging phases, characterize the kinetics and model the time dependent phase formation if possible. For this reason several experimental methods of phase formation were applied after producing calibration samples of defined phases in the laboratory: •Gravity casting with different Al-Fe mass ratios •Wetting experiments under a controlled atmosphere •Dipping trials in pure aluminum and binary commercial alloys •Squeeze Casting of inserts in an industrial environment. The system Al-Si, which is dominant in shape casting industry, produces the most complex phase morphologies with different, simultaneously emerging phases at the interface such as Fe2(Al,Si)5 (η), FeAl4Si (τ6), Fe2Al2Si (τ1) and Fe3Al4Si2 (τ3). This leads to a reduced interface thickness among other things, which has a negative influence on the bonding in the industrial environment. However, it could be also shown that a chemical bonding can add strength to the compound additionally to shape- and force bonding, which range from at least 5 MPa (Al-7Si) to a maximum of 24 MPa (Al 7Zn). Concluding this thesis are practical tips and parameters for the caster on how to obtain chemical bonding in the industrial environment.
Translated title of the contributionUntersuchungen zur Zwischenschichtreaktion von Al und binären Al-Legierungen mit niedriglegierten Stahleinsätzen bei Aluminium-Stahl Verbundguss
Original languageEnglish
QualificationDr.mont.
Supervisors/Advisors
  • Uggowitzer, Peter, Assessor B (external)
  • Antrekowitsch, Helmut, Assessor A (internal)
Publication statusPublished - 2012

Bibliographical note

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Keywords

  • Aluminum
  • Aluminium
  • Steel
  • Iron
  • Hybrid Casting
  • Compound Casting
  • Al13Fe3
  • Al3Fe
  • Al5Fe2
  • Intermetallics
  • Interface
  • Layer Thickness
  • Dipping Trials
  • SEM
  • REM
  • Chemical Bonding
  • Al-Fe
  • Fe-Al
  • Interface Modeling
  • Al-Si-Fe
  • Al-Cu-Fe
  • Al-Mg-Fe
  • Al-Zn-Fe
  • Magsimal59
  • AlSi7Mg
  • AlSi7
  • AlSi12
  • AlSi17
  • Stahl
  • Eisen
  • Hybridguss
  • Verbundguss
  • Leichtbau
  • Hybridbauweise
  • Stahl-Alu
  • Alu-Stahl
  • Intermetallische Verbindungen
  • Verbindungszone
  • Chemischer Verbund
  • Stoffschluss
  • Tauchversuche
  • Interfacemodellierung
  • Wetting Experiment
  • Benetzungsversuche
  • Benetzungswinkel
  • Wetting Angle
  • Mechanical Properties
  • Interface Kinetics
  • Interfacebildung
  • Interface Formation
  • Practical Advice
  • Casting

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