Ahmet Özdemir

Influence of Ce addition on microstructure and mechanical properties of high pressure die cast AM50 magnesium alloy

The influence of Ce addition on the microstructure and mechanical properties of AM50 magnesium alloy was investigated to improve its mechanical properties. The results show that the addition of Ce to AM50 alloy results in the grain refinement and the mechanical properties of the Ce-modified AM50 at room and elevated temperatures are remarkably improved. AM50 magnesium alloy containing 1% Ce (mass fraction) shows better refinement and mechanical properties compared with the AM50 magnesium alloy with 0.5% Ce and even AM50 alloy without any Ce.

Modelling of the cutting forces in turning process for a new tool

In this paper, a neural network model (ANN) was created to predict the cutting forces in turning process for a new tool. A dynamometer was used to measure the static and dynamic cutting forces during the machining process. AISI 4140 steel was used as the work piece material due to its common application in machining industry. Cutting force, thrust force and radial force were measured for three combinations of cutting speeds (V), feed rates (f) and cutting depths (d). The tool angles were kept constant throughout the experiments. Full factorial method was used to design the experiments. For establishing the prediction model, a back propagation network (BPN) was developed with two layers and five neurons. Experimental results were compared with the predicted results of the neural network model (NN). The R2 values for training and test data were obtained 0.9992 and 0.9985 respectively.

The Numerical Analysis of a Mold Cavity Filling Using the Finite Control Volume Method and Comparison to the Experimental Results

One of the most complicated subjects of the injection molding is the flow analysis. The flow of the plastic depends on the structure of the plastic material and the geometry of the mold cavity and the injection process parameters. The flow analysis and the simulations are achieved according to the numerical solution of the non linear differential governing equations. In this study, the Navier-Stokes equations are solved using the Finite Control Volume Method. The staggered grid system is used for the Full Implicit discretization method and SIMPLE algorithm is preferred for the calculation of the pressure. The Boussinesq approach is applicated to determine the density variations and the Power Law viscosity model is choosen. The melt flow is analyzed by Phoenics code. Both numerical analysis and the experiments have been realized for the same processing conditions and the same plastic material. HDPE is studied as a plastic material. It is shown that the theoretical and the experimental results are in good agreement.

Microstructure and Mechanical Properties of High Pressure Die Cast AM50 Magnesium Alloy Containing Ce

Over the past decades, the necessity to decrease the weight of automobile parts has created a considerable interest in magnesium alloys. The need to develop magnesium die casting alloys for car components motivates R&D in high temperature magnesium alloy development. In order to improve magnesium alloys with low cost, high strength and with notable elevated temperature properties, the effect of Ce addition (0.5/1.0 wt.-%) on microstructure and mechanical properties of AM50 was studied. Results show that addition of Ce to AM50 resulted in grain refinement and the formation of the secondary phase Al11Ce3. Mechanical properties of investigated alloys at both room and elevated temperature were remarkably increased. AM50 containing l%wt. Ce showed relatively better refinement and mechanical properties compared to AM50 with 0.5%wt. Ce.