Wear characteristics of GH4169 superalloy at elevated temperatures

Abstract

Nickel-based superalloy GH4169 has gained significant prominence in aerospace and power-generation sectors due to its exceptional resistance to fatigue, creep and corrosion at high temperatures. However, wear on the contact surface remains a concern during its operational lifespan, as it can lead to crack initiation and reduce the service life of the alloy. Therefore, this study aims to comprehensively investigate the dry-sliding wear behaviors of the GH4169 superalloy under various conditions, including temperatures, applied loads and sliding speeds via a ball-on-disc tribometer. The results obtained from the study indicate that the wear rate of the GH4169 superalloy is initially high at room temperature. However, as the temperature increases to 525 °C, the wear rate significantly decreases. Subsequently, with further temperature increase to 650 °C, there is a slight rise in the wear rate. However, the findings regarding the friction coefficient present a conflicting trend compared to the wear rate. Under the same testing conditions, the wear rate of the GH4169 superalloy at 525 °C and 650 °C demonstrates a significant reduction of 21% (0.0774 × 10^–4 mm³/N.m) and 19% (0.0785 × 10^–4 mm³/N.m), respectively; when compared to room temperature (0.0935 × 10^–4 mm³/N.m). Besides, at room temperature, the wear track depths measure approximately 34 ± 2 µm and 55 ± 3 µm for applied loads of 20 N and 60 N, respectively. These values indicate a significant wear depth under ambient temperature conditions. On the other hand, at 525 °C, the wear track depths are slightly lower compared to those at RT. The measured depths at 525 °C amount to approximately 25 ± 2 µm and 38 ± 2 µm for applied loads of 20 N and 60 N, respectively. At high temperatures and low applied loads, the wear mechanism of the GH4169 superalloy is mainly abrasion. However, at low temperatures and high applied loads, the wear mechanism becomes more complex, involving abrasion as well as oxidation, delamination, softening and melting. This study offers valuable insights into how different wear testing parameters impact the tribological characteristics of the GH4169 superalloy.