Mechanical alloying (MA) is a solid-state powder processing technique that was developed in the 1960s to synthesize nickel-based oxide-dispersion strengthened (ODS) superalloys that combine the twin effects of precipitation hardening (for intermediate temperature strength) and dispersion hardening (for elevated temperature strength). These ODS alloys contain very fine, nanometer-sized, oxide (and other ceramic) phase particles to impart the high-temperature strength and can be considered the first nanocomposites synthesized by MA. In comparison to other techniques such as solidification processing or internal oxidation, MA is a simple technique with unique advantages. For example, it is very easy to obtain nanostructures in most cases, a high volume fraction of the reinforcement phase can be introduced into the composite, and consolidation of the milled powder to full density is relatively easy. FLAMINGo applies MA to Aluminium Metal Matrix nanoComposites and combines MA with casting and extrusion to bring the new material to the automotive industry.
The performance of a component can be maximized by using topology optimization. The goal of optimization is the reduction of weight or the improvement of structural stiffness. The optimization process starts with defining boundary conditions like loads, construction space, and additional tasks according to a specific part. The importance of each element for the system will be evaluated and the design variables will be varied. After several iterations, an optimum design will be created.
Low-Pressure Die Casting (LPDC)
This process runs with the utilization of dies, one half of the die is attached to a fixed machine plate and the other to a movable one on a die-casting machine that is vertically aligned. After filling the die, the pressure is maintained as the metal cools to enable the addition of further molten metal to counter any volume deficits (shrinkage cavities) as the metal passes from its molten to solid state. The method can produce components with complex geometries and high dimensional accuracy.
Green Sand Casting (GSC)
In the Green Sand Casting the molten metal is poured into molds. The metal is molten by utilizing induction furnaces. The molds are made of wet sand mixed with bentonite clay or organic binders. The molds can be easily created in automated assembly lines. GSC is the most widely used casting method for small volume components. On the other hand, green sand molds for casting don’t have tight dimensional tolerance, and thus when precise dimensions are required or smooth surfaces the components should be further processed by machining and surface finishing.
Extrusion of Al-MMnC components
Extrusion method is to process complementary to LPDC and GSC supporting the drawbacks and limitations that might occur in terms of processabilities with improvements in the design of the component. Direct chill cast Al-MMnCs billets will be produced and sectioned prior to extrusion. Extrusion of parts is better applied if welding, where casting can be effectively demonstrated in smaller components and results transferred to the whole castable components.
Welding of Al-MMnC components
Welding offers a key range of well-proven possibilities for the construction of aluminium vehicle body structures and closures. Specifically, in the FLAMINGo project, a variety of different processes will be used (MIG welding, resistance spot welding, and arc stud welding). With MIG welding, the use of the pulsed current mode is the most preferred solution for the arc welding of thin- to medium-gauge aluminium structural parts. Resistance spot welding is producing high-quality welds in aluminium, not only in the automotive industry but also in aerospace applications. Arc stud welding uses rather short welding cycles, conditions that may be potentially demanding from the metallurgic point of view and are worth some specific investigation.
For quality control (QC) of manufactured Al-MMnCs components, NDT techniques can be used. Non-destructive testing techniques, include among others: ultrasonic testing, thermography, shearography, and Eddy currents. Other valuable techniques can be also considered, such as Process Compensated Resonance Testing. Those NDT procedures can detect defects and discontinuities inside materials for quality control of the newly manufactured components and quality assurance during service.
Al recycling begins with the separation of aluminium alloys from scraps before remelting and, nowadays, great endeavors are devoted to improve the quality and efficiency of this goal to obtain a final remelted product with tight elemental tolerances. After scrap sorting, remelting is carried out as the last step in the Al recycling value chain to requalify for future use. In the case of AMMnCs it is already known that the wettability and dispersion of the reinforcing nanoparticles cannot be maintained, for the high temperature and prolonged processing times.
MBN Nanomaterialia SPA VIA BORTOLAN 42, CARBONERA , 31030, IT
Project Title: Fabrication of Lightweight Aluminum Metal matrix composites and validation In Green vehicles Topic: LC-GV-06-2020 Advanced light materials and their production processes for automotive applications.
This Project has received funding from the European Community’s H2020 Programme under the grant agreement Nr. 101007011 Funding Scheme: H2020-LC-GV-2020