Effect of Ti Content on Microstructure and Wear Performance of TZM Alloys Produced by Mechanical Alloying Method

In this study, changes in microstructure, hardness and wear performance of titanium-zirconium-molybdenum (TZM) alloys produced by mechanical alloying method with the addition of different amounts of titanium (Ti) were investigated. Mechanically alloyed powders were sintered at 1300 degrees C for 4 h under 10(-6) mbar vacuum environment. The produced alloys were characterized by scanning electron microscope (SEM + EDS), X-ray diffraction, grain size distribution, hardness and density measurements. In the wear tests, three different loads and five different sliding distances were used. Results showed that the produced TZM alloys were porous, and the pores in the alloys containing 0.40% and 0.45% Ti were generally located on the grain boundaries. In alloys containing 0.50% Ti, inside the grain the pore sizes increase, while in the alloy containing 0.55% Ti, the pore sizes in grain boundary decrease. Grain size distribution results show that as the Ti content increased, the amount of grain size over 6 mu m decreased and smaller than 6 mu m increased. Hardness and density results show that while the hardness of TZM alloys produced increases depending on Ti content, their density decreases. The highest hardness was obtained in the TZM alloy containing 0.55% Ti, while the lowest density was obtained in the same alloy. Wear test results show that the lowest weight loss was obtained in TZM alloy containing the highest amount of Ti (0.55%) under all loads. Graphic