An extensive study of the properties of powder metallurgy Al-Si alloys was carried out. The effect of atomization parameters on the power properties, such as their compressibility, were highlighted. We studied the relation between processing parameters as lubrication route (wax addition or die wall lubrication), dewaxing, preheating and forging temperature, which contributed to optimizing the densification parameters for this kind of alloys and powder characteristics. Mechanical properties were determined by tensile and fatigue testing. The results obtained are consistent with other published research work. Unfortunately, we obtained lower values for fatigue tests than expected, due to an unwanted contamination of the original powders by pure Al particles decreasing the fatigue properties. Furthermore, we can note the low toughness of these materials, which has to be accounted (7.0 Mpa m) for while designing structural parts as con-rods. An interesting result concerns the study of tribological behaviour of Al-17Si-5Fe-3.5Vu-1.1Mg-0.6Zr B alloy. This material exhibits very good wear and friction behaviour when in contact with steel, even very hard steel (667 HV). This result can be exploited for further applications.
With regards to the component developed throughout this project, further forging tests would be necessary to perfect the development of the direct forged Al powder metallurgy connecting-rod using industrial equipment.
At the present time, a new code has been developed in order to facilitate the tool design and to predict the densification of such components produced from powders. This code is a 3D compressible viscoplastic version of Forge3 taking into account the thermal coupling and will soon be launched on the market.
The simulation of price for such a component leads to an average value of 5.2 ECU, which is higher than conventional steel products but could be considered with the need of fuel consumption reduction of future cars. This price simulation means that only the holes of the big and small ends and the faces are machined after forging.
This project covers several aspects from the characterization of powder metallurgy (PM) aluminium alloys, the modelling and tools development of a cost-effective shaping process (direct powder forging), to the production of automotive components and their testing.
Direct powder forging of Al high performance alloys offers interesting perspectives for developing low weight automotive components through a combination of the advantages of Al-Si-XPM materials (high strength, low thermal expansion, wear resistance) with the benefits of PM processing, this is net-shaping (high materials yield, reduced processing and machining steps). The implementation of advanced Al PM components engines can reduce the weight of present cast moving parts and thus reduce the polluting emissions of engines. In regard to cast components, significant weight reductions (minimum 30%) and new design are expected for Al automotive components.
The first stage of our work will consist in characterizing the microstructural, physical and mechanical properties of the Al-Si-XPM alloys investigated in this project (material development).
The second and third stages will be optimization of the part geometry, modelling and optimization of the forging parameters (direct powder forging), tool design (processing development), and production of parts for mechanical and engine testing (component development). Cost evaluation for a series production will be considered.
Funding SchemeCSC - Cost-sharing contracts