Mehmet Şimşir

Investigation of Mechanical Properties and Microstructure of AA2024 and AA7075

Aluminum alloys have been extensively used as structural material due to its high strength and damage-tolerance. Alloy 6061, 2024 and 7075 are engineered to be lightweight and strong,and their ease of formability allows complex shapes and drawn parts,which can then be further enhanced with heat treating. In this study is aimed to improve the mechanical properties of aluminum alloys by heat treatment.AA2024 and AA7075 were selected and each alone at T3 and T6 temper conditions has been studied respectively.For the mechanical properties of AA2024 and AA7075 alloyshardness, fatigue behavior, tensile test and charpy impact test with standard V notched specimens at RTand-5 °C were analysed in the present study. Microstructural characterization has been done using standard metallography.

Investigating the effect of testing parameters on adhesive wear using Taguchi method

Abstract The aim of this study is to investigate the effect of working parameters on wear resistance of steels in terms of applied load, hardness and revolution per minute (rpm) using the Taguchi method. Pin-on-roller type of apparatus was used for adhesive wear tests. The operating parameters were investigated by employing the orthogonal array, signal-to-noise ratio and analysis of variance. The experimental wear test results show that the hardness of the materials is the major parameter among the controllable factors. After the hardness, the applied load and the rpm sequentially have influence on the wear resistance of three types of steels; AISI 1050, AISI 4140 and AISI 8620. The best wear testing parameters were determined for current conditions of the steels. A good agreement between the predicted and experimental wear amounts is observed.

Investigation on the machinability of steel/steel laminates by CO2 laser

In this study, an experimental investigation of machinability of steel/steel laminates using CO2 laser was presented. O2 assist gas was used for cutting of laminates. Laser power and feed rate were changed gradually as cutting parameters. Heat affected zone (HAZ) size and kerf width were measured. Effect of linear energy density (ratio of power to feed rate) was determined on the kerf width, the HAZ size, and the cutting surface quality. Also, the quality of surface was examined under optical microscopy, and scanning electron microscopy. It is concluded that when linear energy density is increased, the kerf width and the HAZ size increase. Dross formation and surface irregularities increase with increasing laser power and decreasing feed rate.

Wear Behavior of Diamond+SiCp-Reinforced Metal Matrix Composite by Taguchi Method

Fe-Co based diamond-reinforced composites (D-MMCs) and diamond+SiC-reinforced composites (D+SiC-MMCs) were produced by cold pressing method. Investigation of the wear behaviors on two-body abrasive wear behavior of the composites were carried out under different conditions. 2k factorial designs of experiments were used to obtain the data in a controlled way. The wear parameters studied were sliding speed, load and sliding distance. An orthogonal array and analysis of variance (ANOVA) were employed to investigate the influence of process parameters on the wear resistance of these composites. The results indicated that the incorporation of SiC particles in the metal matrix as a secondary reinforcement increased the wear resistance. In addition to this, the applied load had the significant effect on the weight loss of both types of composites. Furthermore, a correlation was derived from the results of the experimental design by multiple regressions. Finally, confirmation of experiment was conducted to verify the predicted model.