Metals and Ceramics Division - Oak Ridge National Laboratory

Cermet Composites for Wear Applications
R. J. Stafford
Cummins Inc.
Objective/Scope
TiC/Ni3Al is a composite of TiC powder in a Ni3Al matrix which was developed in collaboration
with Oak Ridge National Laboratory (ORNL) and CoorsTek. Its composition was established to
match the unique properties required for Cummins Fuel Systems applications. CoorsTek and
ORNL have developed the processing methods to make the material, while Cummins has been
responsible to finding an application for it and testing the material as fuel system components
and evaluating their performance versus other materials. The objectives of this work are to
characterize the material and optimize the composition and processing. Specific objectives are:
• Optimize injection molding binder composition and sintering cycles to achieve 99+%
density. This will include the determination of the shrink rate during sintering for
prototype tool construction and demonstration.
• Determine production viable sources for all raw components in the composition.
• Test prototype components in intended application on Cummins’ fuel system test rigs to
show viability of material in an application.
Approach
• A prototype injection-molding tool of a proposed Cummins Fuel Systems component will
be made and test pieces of the TiC/Ni3Al cermet will be produced to near-net shape for
evaluation of shrinkage, microstructure uniformity, and density.
• Prototypes machined from isostatically pressed rods of the TiC/Ni3Al cermet will be
tested on abuse tests at Cummins Fuel Systems.
• Production source for NiAl powder will be identified and processing parameters for the
new powder determined to ensure the properties of the final composition do not vary
from the properties of the composition using the original NiAl powder.
Technical Highlights
Ni3Al/TiC Composite
Testing and pending approval of a new source of the critical NiAl raw material from Accumet is
underway. ORNL (Tiegs) has sintered test parts from first prototype design successfully to the
same density as the previous material (from X-Form, now out of business). A test lot of powder
has been processed through milling at ORNL, compounded into feedstock, molded and debound
at CoorsTek, it is waiting for a new sintering trial at Colorado School of Mines (CSM). Some
initial parts sintered at CSM were 97.7% dense; whereas, the parts sintered at ORNL were 98.8%
dense.
From these tests, we will measure a final shrinkage to create the mold for the revised prototype
part. The part was redesigned to add stock for fixturing during the finish grinding operations at
Cummins.
.