Sürdürülebilir Kalkınma Amaçları

• 1

• MakaleYalnız künye2025/r/gumushane/19645
  Effect of Chromium Addition on ZA40 Alloy Fabricated by Powder Metallurgy Method

  Aydin, Kemal

  The aim of this study is to develop and investigate the properties of chromium powder-reinforced metal-metal composites using powder metallurgy methods with a ZA40 alloy matrix. To analyze the effect of varying chromium particle amounts on ZA40-Cr composites, samples with chromium weight percentages of 5%, 10%, and 15% were produced. To ensure uniform distribution of chromium particles, the matrix and composite powders were mixed in ball mills for five hours. These powders were then hot-pressed under an argon gas atmosphere at 500°C and 500 MPa pressure for two hours to form the samples. The samples were evaluated by determining the microstructure, hardness, density, and tensile properties of the ZA40-Cr metal-metal composites with varying chromium content. Porosity and relative density results revealed that increasing Cr content increased porosity while reducing relative density. Hardness measurements showed that the sample with 10% Cr addition exhibited the highest hardness value (182 Brinell). However, increased porosity in the 15% Cr sample caused a decline in hardness. Tensile strength tests indicated that the sample with 10% Cr addition achieved the highest strength (240 MPa). The results demonstrated that the reinforcement of the ZA40 matrix with Cr particles at specific ratios enhanced the mechanical performance, but that excessive Cr content adversely affected the properties due to increased porosity. The optimum Cr content was determined to be 10%, providing the best mechanical properties. This study highlights the potential of ZA40-Cr composites as cost-effective and high-performance materials for engineering applications.

  • 
  İncele
• MakaleAçık Erişim2022/r/gumushane/17162
  Gyroscopic Vibration Damper for Building: Theoretical and Experimental Research

  Ünker, Faruk; Cuvalci, Olkan

  In this study, a gyroscopic damper model consisting of a built-in column has been developed. The objective of this study is determining the required angular momentum with the optimum ratio of natural frequency for the gyroscopic vibration absorber under sinusoidal excitation. This damper model is investigated experimentally and theoretically for different angular momentums of the gyroscope and different frequency ratios of the structure and damper on a single-story structure. As a result of the study, the displacement of the structure at the 1st mode frequency for a given angular momentum of the gyroscope is fairly reduced. Besides, at a notable frequency ratio of the damper and the structure, the effect of the angular momentum is improved. Even if the disk mass of the gyroscope decreases, it is possible to obtain a certain angular momentum by increasing the disk speed. Thus, lighter and less bulky gyroscopic vibration dampers can be designed. The cooperation of the required angular momentum with the optimum ratio of natural frequencies should be considered to obtain a highest attenuation of the building vibration. In addition, the equations of motion obtained according to the 1st mode and the theoretical results overlapped.

  AtıfOpenAlex6

  İncele