Elucidating the tribological behavior of solid-state and liquid phase sintered tungsten heavy alloys

Abstract

This study investigates the influence of sintering mechanisms on the tribological performance of tungsten heavy alloys (WHAs) with a nominal composition of 90W-8Ni-2Co (wt%). WHAs were fabricated at two distinct temperatures, 1330 degrees C and 1480 degrees C, for 90 min under hydrogen atmosphere. To support the evaluation of tribological performance, a supporting analysis of sintering behavior and microstructural evolution was conducted across both temperature regimes. Microstructural characterization and phase analysis were conducted using Scanning electron microscopy and X-ray diffraction, respectively. The sintered alloys exhibited significant differences in hardness, with values of 237 HV0.5 and 366 HV0.5 for samples sintered at 1330 degrees C and 1480 degrees C, respectively. Tribological properties were assessed under dry sliding conditions using a reciprocating wear test configuration. Results revealed a substantial reduction in wear rate with increasing sintering temperature; specifically, a decrease from 3.45 x 10-3 to 2.36 x 10-3 mm3/m. The coefficient of friction was observed to decrease with increasing load, ranging from 0.57 to 0.34 for the WHA sample sintered at 1330 degrees C, and from 0.43 to 0.22 for the sample sintered at 1480 degrees C. Examination of the worn surfaces indicated the activation of multiple wear mechanisms, including adhesive wear, abrasive wear, and oxidative wear. The findings underscore the critical role of sintering temperature in optimizing the mechanical and wear performance of WHAs. The counterbody was characterized and found to exhibit adhesive wear features.