Ni3Al-Based Composites as Alternative Die Materials for the Extrusion of Hard Aluminum Alloys
Twan J. Walstock, Adex B.V.
Jie Zhou and Jurek Duszczyk, Delft University of Technology
Track: DIE DESIGN AND TECHNOLOGY - Surface Treatments and Materials
ABSTRACT --- Having a good combination of mechanical and tribological properties,
H13 and H11 have long been accepted as standard materials for aluminum extrusion
dies. Efforts to improve the performance and lifetime of tool steel dies have mostly
been concentrated on die surface enhancement. The success in developing and
applying new die materials has been very limited. In the present work, Ni3Al
intermetallic compound and their composites containing TiC particles were selected as
alternative die materials, to take advantage of their unique characteristic variation of
yield strength with temperature up to about 700 0C. These materials are electro-
discharge machinable and the dies so manufactured have a significantly reduced
thickness of the white layer. Extrusion experiments using dies made of these materials
showed excellent deformation resistance against very high specific pressure, good
wear resistance, and reduced interactions with the billet material. These features are of
particular significance for the extrusion of hard aluminum alloys. Indeed, the
permissible billet temperature and ram speed for a 7075 alloy, for example, could be
considerably increased. In addition, the dies made of these materials do not need
nitriding and the time for die stripping is much shorter. These results demonstrate great
potential for commercial applications.
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