Massachusetts Institute of Technology

US Government As Represented by the Secretary of the Army

Heather Ann Murdoch

Christopher Allan Schuh

Kristopher Allen Darling

Billy C Hornbuckle

John J Pittari, Iii

Steven M Kilczewski

Jeffrey J Swab

Robert J Dowding

Laszlo John Kecskes

Anthony James Roberts

Scott Martin Grendahl

Thomas Lee Luckenbaugh

Kiran N Solanki

A sintered cemented carbide body including tungsten carbide, and a substantially cobalt-free binder including an iron-based alloy sintered with the tungsten carbide. The iron-based alloy is approximately 2-25% of the overall weight percentage of the sintered tungsten carbide and iron-based alloy. The tungsten carbide may be approximately 90 wt % and the iron-based alloy may be approximately 10 wt % of the overall weight percentage of the sintered tungsten carbide and iron-based alloy. The tungsten carbide may comprise a substantially same size before and after undergoing sintering. The iron-based alloy may be sintered with the tungsten carbide using a uniaxial hot pressing process, a spark plasma sintering process, or a pressureless sintering process. The sintered tungsten carbide and iron-based alloy has a hardness value of at least 15 GPa and a fracture toughness value of at least 11 MPa&#x221a;m.

Cemented carbide containing tungsten carbide and fine grained iron alloy binder

Identifying a stable phase of a binary alloy comprising a solute element and a solvent element. In one example, at least two thermodynamic parameters associated with grain growth and phase separation of the binary alloy are determined, and the stable phase of the binary alloy is identified based on the first thermodynamic parameter and the second thermodynamic parameter, wherein the stable phase is one of a stable nanocrystalline phase, a metastable nanocrystalline phase, and a non-nanocrystalline phase. In different aspects, an enthalpy of mixing of the binary alloy may be calculated as a first thermodynamic parameter, and an enthalpy of segregation of the binary alloy may be calculated as a second thermodynamic parameter. In another example, a diagram delineating a plurality of regions respectively representing different stable phases of at least one binary alloy is employed, wherein respective regions of the plurality of regions are delineated by at least one boundary determined as a function of at least two thermodynamic parameters associated with grain growth and phase separation of the at least one binary alloy.

Stable binary nanocrystalline alloys and methods of identifying same

Cemented carbide containing tungsten carbide and finegrained iron alloy binder

A method for screening a large design space of compositions with possible application as binders in cermet and powder metallurgy applications allows rapid elimination of large portions of the design space from contention so that resource intensive procedures, such as computationally intensive modeling techniques and experimental testing, can be focused on potential binder compositions with a high likelihood of being used successfully. The method relies on parameters such as surface tension, contact angle, viscosity, a special capillary metric that is used to characterize capillary behavior, and melting point, which are relatively easy to calculate or determine, to screen out large portions of the design space. Exemplary binder compositions are obtained using the method.

Process for guiding rapid development of novel cermets

Novel metallic systems and methods for their fabrication provide high temperature machine parts formed of a consolidated nano-crystalline metallic material. The material comprises a matrix formed of a solvent metal having a melting point greater than 1,250&#xb0; C. with crystalline grains having diameters of no more than about 500 nm, and a plurality of dispersed metallic particles formed on the basis of a solute metal in the solvent metal matrix and having diameters of no more than about 200 nm. The particle density along the grain boundary of the matrix is as high as about 2 nmof grain boundary area per particle so as to substantially block grain boundary motion and rotation and limit creep at temperatures above 35% of the melting point of the consolidated nano-crystalline metallic material. The machine parts formed may include turbine blades, gears, hypersonics, radiation shielding, and other high temperature parts.

Nanocrystalline high temperature machine parts

Provided in one embodiment is a method of identifying a stable phase of an ordering binary alloy system comprising a solute element and a solvent element, the method comprising: determining at least three thermodynamic parameters associated with grain boundary segregation, phase separation, and intermetallic compound formation of the ordering binary alloy system; and identifying the stable phase of the ordering binary alloy system based on the first thermodynamic parameter, the second thermodynamic parameter and the third thermodynamic parameter by comparing the first thermodynamic parameter, the second thermodynamic parameter and the third thermodynamic parameter with a predetermined set of respective thermodynamic parameters to identify the stable phase; wherein the stable phase is one of a stable nanocrystalline phase, a metastable nanocrystalline phase, and a non-nanocrystalline phase.

Stable nanocrystalline ordering alloy systems and methods of identifying same

Identifying a stable phase of a binary alloy comprising a solute element and a solvent element. In one example, at least two thermodynamic parameters associated with grain growth and phase separation of the binary alloy are determined, and the stable phase of the binary alloy is identified based on the first thermodynamic parameter and the second thermodynamic parameter, wherein the stable phase is one of a stable nanocrystalline phase, a metastable nanocrystalline phase, and a non-nanocrystalline phase.

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Baltimore, MD, United States of America

Heather Ann Murdoch