PROPRIETARY MATERIALS TECHNOLOGY
Technology Value Proposition
HybriMet™ Zero Contiguity Metal Matrix Composite
Composite technology offers a way to engineer tensile strength and hardness in a metal, either pure or an alloy, independent of the metal composition. The metal or alloy can be compounded for corrosion resistance, processability, moldability and then reinforced by composite fillers. Pure nickel, which has a tensile strength of about 180 MPa can be reinforced by ceramic nanoparticles to achieve a tensile strength over 1000 MPa. Separating strength from the metal properties, and the choice of ceramic type and concentration in the composite enables the material to be tailored for thermal expansion, corrosion resistance, etc. This provides a platform technology that can be manipulated by materials engineers to solve problems that are very difficult today.
Zero contiguity in the HybriMet™ metal matrix ceramic nanocomposite is key to achieving high strength and toughness. Zero-contiguity refers to the property of a two-phase composite material where no two particles of the discrete constituent are in contact with one another. HybriMet™’s unique process achieves the near zero contiguity goal, maximizing the interface area of the reinforcement to the matrix.
HybriMet™’s nanocomposite consists of metal and ceramic where the metal matrices used include cobalt (Co) and nickel (Ni) and the ceramics include titanium nitride (TiN), tungsten carbide (WC) and silicon carbide (SiC). HybriMet™ hierarchically engineers the nanocomposite structure by coating nano-particles of ceramic with an appropriate metal alloy, coating the resulting particle with the metal matrix and then compacting and sintering the material in a controlled process to carefully control porosity and grain growth.
HybriMet™ is a family of hierarchically structured ceramic-metal (cermet) nanocomposites with superior wear resistance, lower friction, higher fracture toughness, and improved reliability and durability compared to conventional materials including tool steels and ceramics. The structure combines high hardness nanocomposite zones with tough ductile zones in an engineered manner, resulting in a composite material that has mechanical properties higher than tool steel (29.5 MPa/m1/2 toughness).
The nickel matrix reinforced with WC composite has a room temperature tensile strength of 944 MPa, higher than either Cartech L-605, Haynes 230, Hastelloy C276, Inconel 655 or other superalloys. HybriMet™ provides the frictional and life benefits of ceramics such as Si3N4, but with the toughness and ease of manufacture and reliability of steel.
The demonstrated HybriMet™ nanocomposite materials offer very low friction when tested with a minimal amount of poorly lubricating fluids, and are extremely erosion and wear resistant, offering erosion and wear resistance similar to diamond-like carbon and CrN coatings (in air). Tribological tests conducted during research have shown extremely low wear in both dry and in lubricated environments, encouraging continued development as rolling elements in ball and roller bearings and as plain bearings (bushings). When tested dry, without any lubricant, the coefficient of friction is 0.5.
HybriMet™ is consolidated using spark plasma sintering (SPS) or applied as a coating using a High Velocity Oxygen Fuel (HVOF), a thermal spray coating process that provides a supersonic jet of hot, high-velocity gas (from burning fuel and oxygen) to propel powdered materials onto a surface, creating extremely dense, hard, and wear-resistant coatings, often replacing traditional hard chrome plating for extended component life in harsh conditions. It’s favored for its superior bond strength, low porosity, and excellent hardness, making it ideal for parts needing protection from abrasion, erosion, and corrosion. The SPS process allows molding the material with very controlled grain growth. Because the sintering cycle can be run without melting the metal matrix, the dispersion of the ceramic phase can be maintained, and the ceramic elements do not alloy with the metal matrix. This preserves the engineered hierarchical structure of the composite.
The coating of the ceramic powder has been run at the rate of several tons per year, so the production costs of the HybriMet™ materials are well understood. The composite is readily machinable using EDM and grinding techniques. Most importantly, no complex and costly heat treating and no touch-up machining are required to attain the composite’s properties.
HybriMet™ zero contiguity metal matrix ceramic nanocomposite is a platform technology that offers economy and flexibility to engineer the material properties for a variety of parts for extreme environments.
The NEXT GENERATION of Engineering Materials
- The hardness of ceramics and toughness exceeding tool steel.
- Offers exceptional mechanical, tribological, and wear performance.
- Allows large parts to be fabricated without the flaw sensitivity of monolithic ceramics.
- Low friction and wear in low viscosity lubricants, e.g., salt water or diesel fuel.
- Superior corrosion and wear resistance in chloride, FLiBe, FLiNaK salts.
- Very low porosity with coatings much thinner than other materials.
- Excellent adhesion to substrate through thermal cycling.
- No valve plug welding during long duration closures in hot salts.
- A low-Cobalt composition for nuclear applications.
- Low wear on mating surfaces.
- No requirement for heat treatment.