The Effect of Iron as a Trace Impurity on the Sintering of 2xxx Series Aluminium Alloys

摘要

The need to reduce vehicular emissions and increase fuel economy has seen the automotive industry introducing more lightweight components. When appropriate, the replacement of steel with aluminium alloys is one way to achieve these weight reductions. Aluminium powder metallurgy is an inexpensive production route for some of these components. Powder metallurgy sintered aluminium alloys are sensitive to a variety of trace alloy additions. Here we show that iron as a trace impurity, effects the microstructure and properties of the Al-4.4Cu-0.15Mg alloy studied. The major affect of iron on the microstructure is to increase the number of intragranular liquid pools, which have a similar composition to the Al-Cu eutectic sintering liquid. We propose a model for the liquid pool formation, based on analytical SEM and TEM analysis, and the mechanism by which iron effects 2xxx series aluminium alloys.