High Temperature Wear Property of Ta-10W Alloy

초록

This study investigated the high-temperature wear characteristics of Ta-10W alloy, composed of 90% tantalum and 10% tungsten, known for its high melting point, excellent corrosion resistance, and oxidation resistance. Wear tests were conducted using a ball-on-disc method with alumina balls at temperatures of 200 degrees C, 400 degrees C, 600 degrees C, and 700 degrees C. The results indicated that wear loss decreased (increasing wear resistance) from 200 degrees C to 600 degrees C due to the lubrication effect by oxide particles induced by Ta2O5, which enhanced wear resistance. However, at 700 degrees C, a significant increase in wear loss was observed due to excessive oxide formation and the occurrence of cracks. Calculation of the wear rate revealed that it decreased as the temperature increased to 2.12x10(-4) mm(3)<middle dot> N-1<middle dot> m(-1) at 200 degrees C, 2.67x10(-5) mm(3)<middle dot>N-1<middle dot>m(-1) at 400 degrees C, and 4.21x10(-6) mm(3)<middle dot> N-1<middle dot> m(-1) at 600 degrees C. On the other hand, the wear rate increased at 700 degrees C to 3.87x10(-4) mm(3)<middle dot> N-1<middle dot> m(-1). The wear track analysis results revealed distinct wear mechanisms at different temperatures. At 200 degrees C, abrasive wear characterized by pits and furrows was dominant. At 400 degrees C, adhesive wear became more prevalent with cleavage worn surfaces compared to the wear pattern at 200 degrees C. At 600 degrees C, fragmented oxides indicating pest oxidation were noted, while at 700 degrees C, deep pits and cracks along with fragmented oxides were prevalent. X-ray diffraction (XRD) analysis results showed the presence of the alpha-Ta phase at 200 degrees C, 400 degrees C, and 600 degrees C, with peak shifts indicating lattice expansion. In contrast, at 700 degrees C, Ta2O5 peaks were present. Based on the findings, the high-temperature wear mechanism of Ta-10W alloy was also discussed.

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