Olufayo Oluwole A, Che Hanqing, Songmene Victor, Katsari Christina, Yue Stephen
Department of Mechanical Engineering, École de Technologie Supérieure, ÉTS, Montreal, QC H3C 1K3, Canada.
Department of Mining and Materials Engineering, McGill University, Montreal, QC H3A 0C5, Canada.
Materials (Basel). 2019 Jun 25;12(12):2034. doi: 10.3390/ma12122034.
Nickel-based superalloys are heavily used in the aerospace and power industries due to their excellent material and mechanical properties. They offer high strength at elevated temperatures, high hardness, corrosion resistance, thermal stability and improved fatigue properties. These superalloys were developed to address the demand for materials with the enhanced heat and stress capabilities needed to increase operational temperatures and speeds in jet and turbine engines. However, most of these properties come with machining difficulty, high wear rate, increased force and poor surface finish. Rene 65 is one of the next generation wrought nickel superalloys that addresses these demands at a reduced cost versus powder metallurgy superalloys. It is strengthened by the presence of gamma prime precipitates in its microstructure, which enhance its strength at high temperatures. Notwithstanding its advantages, Rene 65 must also deal with the reality of the poor workability and machinability generally associated with Ni-based superalloys. This study examines the machinability-using drilling tests-of Rene 65 and seeks to establish the influence of hardness (with varying microstructure) and cutting conditions on machinability indicators (surface finish, forces and chip formation). The experimental setup is based on a set of experimental drilling tests using three different heat-treated samples of varying hardness. The results indicate a negligible effect from material hardness, ranging from 41 HRC to 52 HRC, on generated cutting forces and a similarly low effect from cutting speeds. The feed rate was identified as the main factor of relevance in cutting force and chip morphology during the machining of this new superalloy.
镍基高温合金因其优异的材料性能和机械性能而广泛应用于航空航天和电力行业。它们在高温下具有高强度、高硬度、耐腐蚀性、热稳定性以及改善的疲劳性能。这些高温合金的开发是为了满足对具有更高热性能和应力性能的材料的需求，以提高喷气发动机和涡轮发动机的运行温度和速度。然而，这些性能大多伴随着加工难度大、磨损率高、切削力增加以及表面光洁度差等问题。Rene 65是下一代变形镍基高温合金之一，与粉末冶金高温合金相比，它以更低的成本满足了这些需求。它通过在微观结构中存在γ'相沉淀而得到强化，这增强了其在高温下的强度。尽管具有这些优点，但Rene 65也必须面对镍基高温合金通常存在的加工性能差的现实。本研究通过钻孔试验研究了Rene 65的可加工性，并试图确定硬度（具有不同微观结构）和切削条件对可加工性指标（表面光洁度、切削力和切屑形成）的影响。实验装置基于一组使用三种不同硬度的热处理样品的钻孔试验。结果表明，材料硬度在41 HRC至52 HRC范围内对切削力的影响可忽略不计，切削速度的影响同样较小。在加工这种新型高温合金时，进给速度被确定为与切削力和切屑形态相关的主要因素。
