MICROSTRUCTURE ANALYSIS OF MACRO AND MICRO HARDNESS METHODS OF SAMPLES PRODUCED BY POWDER METALLURGY OF ENGINEERING MATERIALS
Project no. 776 · Status: Kapanmış · 2016
Summary
Within the scope of this project, various studies have been realized and the effects of parameters effective in powder metallurgy method on the mechanical properties of materials have been investigated statistically. Compressive strength test from mechanical properties With the Tensile Testing device in the Biomechanics Laboratory of the Mechanical Engineering department; The hardness was made with the Rockwell, Brinnell, Vickers combined hardness device purchased under the project. Central Composite Design (CCD) was used as the statistical experiment design method. In one of the studies, the effect of the mechanical grinding time, hot press sintering temperature and duration of magnesium powders on the mechanical properties of the material was investigated. It is seen that the increase of mechanical grinding time, sintering temperature and sintering time positively affect the Brinell hardness values and increasing these values will provide some increase in hardness values. In general, it has been observed that after 36 hours of mechanical grinding, the increase in mechanical grinding time and sintering temperature causes a decrease in density values; It is seen that the compressive strength increases until the mechanical grinding time is 36 hours and then decreases. In another study, 5 different Mg-Zn alloy ratios were determined and the abrasion resistance, mechanical, hardness and microstructure properties of these ratios were investigated experimentally and statistically. Powder particles were alloyed by mechanical alloying method, alloy materials were sintered by hot-pressing by powder metallurgy method. Compression test, pin on disc wear test, Vickers hardness test was applied to the produced materials, their microstructures were examined, and their porosity ratios were determined and evaluated. It was found that the wear resistance increased up to about 7% Zn despite the negative impact of the pore ratio, the structure consisted of the Mg / (Mg-Zn) microstructure, in this case, it positively reflected on the wear resistance. When the Zn ratio exceeds about 7%, it is seen that there are independent Zn particles in the microstructure and the structure is formed as Mg / (Mg-Zn) / Zn triple-phase. Porosity ratio increased with independent Zn increase in the structure, and it was observed that the wear resistance developed in line with the decrease. Keywords: Powder metallurgy, magnesium, hardness, mechanical alloying