This Small Business Innovation Research Phase I project will evaluate and demonstrate the feasibility of using low nano-aluminum forgings in connecting rod and wheel-based applications. To date, no approaches have proved cost-effective for significantly reducing the mass of driveline components such as the crankshaft, connecting rods and valvetrain. Mass reduction of these moving components would significantly increase fuel economy and engine performance, yet there has been a resistance to mass-reduction efforts in large volume applications. This program will prepare ductile phase toughened nano-aluminum composite billet forgings and characterize mechanical properties before and after aging at 200°C. The program encompasses powder preparation, degassing, consolidation, forging, and mechanical property characterization of 2218-6061 aluminum alloys. The results of this research is to clearly show that one can get decent ductility without sacrificing strength in nanocrystalline alloys by controlling structure at the meso-scale. In fact, the strength can be made higher due to precipitation (ageing), even though this processing step partly recovers the grains and improves the ductility. Other dual-phase microstructures, such as those in steels involving ultrafine martensites, are also advantageous in offering a good combination of strength and ductility.
The broader impact/commercial potential of this project will encourage the use of lightweight alloys in the automotive field by providing a drastic material and manufacturing cost reduction compared to titanium. Currently, the automotive market of connecting rods is mainly oriented to components built with ferrous material because manufacturing and design methodologies are well consolidated and high performances are obtained with minimum cost. However, the use of lightweight materials, i.e., titanium alloys, seems a very attracting alternative, but is still restricted to high performance engine sectors because of the high cost involved. The main advantages are the mass reduction; that is a crucial topic for components subjected to very high inertial loads. Furthermore, the very good fatigue behavior of such materials, meets very well for the requirement to withstand cyclic loads. Other markets including sporting equipment, including bats, tennis racquets, and golf club heads and shafts offer significant performance-driven niches that could be potential commercial beachheads markets. Portable military equipment, such as human robotic extensions, lightweight pack frames, computer housings, and similar military niche markets would be among the initial markets targeted for these materials. Military armored vehicles are also a large potential application for this high strength, high hardness alloy.
This Phase I project sought to evaluate the feasibility of using powder aluminum forgings in connecting rod applications. Mass reduction of critical engine parts has long been an attractive concept but has been inhibited by the large strength requirements. To date, mainly ferrous alloy forgings have been used to make connecting rods due to their low cost, ease of manufacture, and high strength. However, as there is more of a push to reduce consumption of fossil fuels, mass reduction is needed to ensure higher fuel efficiency. The proposed project sought to provide a lower cost alternative to titanium alloys while maintaining a high strength-to-weight ratio and increasing ductility. In this project, 2218 aluminum powder was processed using proprietary milling procedures and consolidated using different methods. The primary method of compaction was sealing the powder within a steel can, and hot forging using a single quick compaction. Other consolidation routes such as hot pressing, cold isostatic pressing and spark plasma sintering were also investigated. In an effort to increase the strength and toughness of the final product, 2218 milled powder was blended with commercially available aluminum powder and boron carbide powder. The project resulted in an establishment of an effective milling procedure and creation of in-house facilities capable of producing and consolidating metal powders. The results obtained are important in considering the processing conditions that will be emphasized while moving forward into Phase II.
