چكيده به لاتين
The present study aims to investigate the influence of reinforcement filling strategy on the particle distribution and mechanical properties of ZA27/TiH2 composites fabricated through friction stir processing. For comparison, the microstructure and mechanical properties of the base material and the unreinforced FSP sample (Reference materials) were also studied. In the current work, all process parameters such as volume fraction of particles were considered constant, but the filling strategy of particles was taken as a variable. Herein, groove-filling and hole-filling methods were utilized for the pre-deposition of particles. Pass number, traverse speed, and rotational speed of the tool were considered two, 50 mm/min and 600 rpm respectively. After metallography, the microstructure and particle distribution were analyzed using optical and scanning electron microscopes. Particle distribution plays a decisive role in the mechanical properties of composites. Therefore microhardness, tensile, and wear tests were also performed. The results showed that the particle distribution in the hole-filling methods is more uniform than groove-filling methods. In addition, among hole-filling methods, those which contained more holes with smaller diameters exhibited homogenous particle distribution and fewer defects than others. Further characterization revealed that the mechanical properties of the linear pattern were higher than the zigzag pattern and even the base material, so the failure of this composite occurred in the base material. However, the mechanical properties of other composites such as hardness, strength, and elongation were found lower than reference materials due to the agglomeration of particles. The wear test results showed that the wear resistance of the unreinforced FSP sample decreased as compared to base material whereas improved by adding reinforcement particles into two linear rows of blind holes.
