Nanocomposite aluminum alloys shops increased ductility and strength

Tweet Abakan portfolio company Powdermet, Inc. (www.powdermetinc.com) announces it has made significant advancements in the performance levels of forged nanocomposite aluminum alloys. Working with the U.S. Army, Powdermet’s nano/micro-aluminum composites have achieved 30-50% higher ductility than traditional high strength aluminum alloys such as aluminum-lithium. Powdermet has devised a powder metallurgy process allowing the retention of nano-crystallites and ductile phases throughout the powder forging process, resulting in near-net shape, high strength aluminum materials having over 16% elongation to failure strengths, exceeding 350MPa (50KSI). Competing aluminum-lithium high strength alloys have tensile strengths of 50-70ksi at 8-12% elongation, whereas the nanocomposite materials are showing 50-72ksi with 7-16% elongation depending on forging conditions. Powdermet has also shown nanocomposite aluminum alloys with up to 200ksi strengths with 1-2% elongation. Current product development goals are to continue process development to achieve a 100ksi, 8% ductility system that is cost-effective and utilizes no costly strategic or rare-earth alloying additions, and to demonstrate repeatable large cross-section part manufacturing using Powdermet’s unique small footprint 5000-ton press and related equipment in its newly acquired and refurbished multimillion dollar Deformation Processing Center.

Powdermet is also please to announce it has joined a joint venture development team with Oshkosh Defense, Eck Industries, and the University of Wisconsin-Madison for “Transformational Technology for Fabrication of Ultra-High-Performance Lightweight Aluminum and Magnesium Nanocomposites.” This partnership will develop and produce lighter, stronger aluminum and magnesium structural components “that will revolutionize the lightweight structures marketplace.” The program goal is to achieve low cost, high strength aluminum materials with strength of steel, but at much lower weight. Other members of the research team include Oshkosh Corporation, an Oshkosh WI, specialty truck builder, Eck Industries Inc., a Manitowoc, WI, aluminum foundry; and project leader, the University of Wisconsin-Madison. Powdermet, Inc. explains this joint venture will allow it (and its partners) to expand the use of nanocomposites beyond their current use by greatly reducing the cost of these unique materials, and by taking their application from simple molded or machined parts into larger, complex metal castings. The work will expand on laboratory tests conducted by the team’s project leader, the University of Wisconsin-Madison, show that incorporation of nanoparticles can greatly increase the performance of aluminum alloys at lower cost than rare-earth additions. However, due to their microscopically small size, nanoparticles are difficult to disperse homogeneously throughout a casting or billet, which is where Powdermet’s expertise and capabilities have been brought into the partnership. The research aims to develop a cost-effective fabrication technology that allows light metals to be strengthened with nanoparticles in large-scale production.

Micro/Nanocomposite Metals

MComP™ (Micro/Nanocomposite) hierarchically-structured super metals offer very high strength-to-weight ratios in magnesium and aluminum alloys. Powdermet offers services for mechanical alloying of micro- and nano-metallic systems including nano-Al, and nano-ceramic additions to metallic alloys. Nano/microstructures are of great interest due to their duplex structure, giving better than rule of mixture properties, enabling very high strength, yet still ductile metallic systems, using Al, Mg, Ti, Fe and other base materials.

AlLiB-MComP™ is a traditional metal matrix composite that is created using powder metallurgical techniques combining aluminum with two other lightweight and high specific stiffness metals: boron and lithium, at the nano-level. The combination of these lightweight (lithium 0.5g/cc) and high modulus (boron E=400GPa) reinforcements allow Powdermet to greatly exceed standard aluminum properties by a nanoengineering process and still retain the weight savings that the lithium gives the alloy.

These powder metal parts are mechanically alloyed, canned and then consolidated to 80% density. Final consolidation is performed using extrusion, rolling and quasi-isostatic forging to produce the final part at a density of 2.5g/cc. The final parts can be annealed or aged and are available in rod, bar, tube, plate, sheet and some near-net and net shape parts.
MComP™ Advantages:

Enable 100% uniform loading of phases
Enables unique property mixtures
Built-in control over interface properties and phase distribution
Nano-level control over phases/chemistry
Non-equilibrium microstructures
Takes advantage of nano-grain property enhancements (strength, hardness, wear resistance, corrosion resistance)

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