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The maintenance cost of a heavy truck increases due to the severe damage of thrust washer in the differential. The wear was usually related to the contact stress concentration. In the study, the finite element analysis (FEA) was performed for identifying the source of the abnormal wear of thrust washer. An improved approach of modifying the surface profile of spider gear back was proposed. FEA simulations were further conducted to investigate the effect of different spider gear back parameters on the tribological behavior of thrust washer. The FEA simulation results were verified by tribological experiments. Results showed that: (i) the abnormal wear of thrust washer pairing the original gear was caused by the local stress concentration; (ii) the local stress concentration could be eliminated by modifying the surface profile of spider gear back; (iii) using the modified spider gear back, the wear mass loss of the thrust washer was reduced significantly; (iv) the promising surface radius of spider gear back was 73.15 mm. [ABSTRACT FROM AUTHOR]

TiZrHfTa 0.5 refractory high-entropy alloy (RHEA) shows great strength and ductility trade-off at ambient temperature, and has a lot of potential for use at elevated temperature. In this work, the effect of B element addition on the wear properties at different temperatures was thoroughly investigated. The results revealed that 1 at% B addition sample presents the best tribological properties at elevated temperatures, and borides exhibit a morphology evolution from blocky to acicular with the increasing B content. The wear rates at ambient and elevated temperatures successfully decrease with the increasing B content, which is ascribed to the increasing hardness, the solution strengthening, and the pinning effect at the grain boundaries induced by the second phase. In addition to the B content, the wear test temperature also significantly affects wear properties. With the analysis of the wear behavior and worn surface, it is demonstrated that the lowest wear rate at 600 ℃ is attributed to the continuous and densified oxide layer, while the serious wear at 400 ℃ results from the uncovered matrix and loose oxide layer. This work offers a new method to improve the wear properties of RHEAs at ambient and elevated temperatures. • The addition of B element for TiZrHfTa 0.5 RHEA results in the preferable wear performance at RT, 400 ℃ and 600 ℃. • The wear performance at 600 ℃ for four types of samples present the lowest wear rate. • The continuous and densified oxide layer formed at 600 ℃ contributes to the lowest wear rate. • The loose oxide layer formed in 400 ℃ leads to more metal fragments and more serious wear. [ABSTRACT FROM AUTHOR]