Effect of Mechanical Milling on the Mechanical, Dry Sliding Wear, and Impact Response of Sintered Nickel Based Superallo
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JMEPEG https://doi.org/10.1007/s11665-020-05256-0
Effect of Mechanical Milling on the Mechanical, Dry Sliding Wear, and Impact Response of Sintered Nickel Based Superalloy Bukola Joseph Babalola, Smith Salifu, and Peter Apata Olubambi Submitted: 2 August 2020 / Revised: 14 September 2020 / Accepted: 3 October 2020 In this study, effect of mechanical milling on the mechanical, dry sliding wear and impact response of spark plasma sintered Ni-17Cr6.5Co1.2Mo6Al4W7.6Ta superalloy has been investigated. Two nickel-based superalloy were sintered, firstly in their as-received elemental particle sizes, while the matrix, nickel of the second alloy, was milled to 10 h prior blending with other elements and subsequent sintering. The impact response was explored using computational modelling approach via finite element analysis, Abaqus CAE/ 2019. Results show that the superalloy with the milled nickel powder exhibited better mechanical properties such hardness, elastic modulus, elastic and plastic strain from impact response than the superalloys with unmilled nickel. Sliding wear tests under dry sliding conditions at three different loads of 20, 25 and 30 N revealed that the superalloy with the milled nickel have lower wear rate when compared to the other with unmilled nickel. It was observed that the wear rate reduced unexpectedly at the applied load of 30 N which may be attributed to the continuous formation of tribo-oxide layer from retained wear debris on worn surface. Keywords
hardness, modelling, superalloys, wear
spark
plasma
sintering,
1. Introduction The growing interest in the development of nickel-based superalloy via advanced processing routes since the 1990s has been poised towards enhanced energy production and aerospace engine performance (Ref 1). Nickel-based superalloys are utilized in the high temperature regime of turbines in power plants (Ref 2, 3) marine and aerospace engines (Ref 4) and are suitable replacements for steel components in these environments as a result of their superior mechanical strength retention and excellent corrosion and oxidation resistance properties (Ref 1, 5-7). There have been historical advancement in the development of nickel-based superalloys which have resulted into improvement in the superalloysÕ performance in service. According to Sommitsch et al. (Ref 8), operating temperature of superalloy increases by the use of investment casting production route in the 1940s, while the reduction in contamination and control of the chemistry and microstructure was achieved via the introduction of vacuum melting in the 1950s. However, these conventional processing routes contribute defects such as poor density, low hardness and strength at relatively elevated temperatures, microstructures with high
Bukola Joseph Babalola and Peter Apata Olubambi, Centre for Nanomechanics and Tribocorrosion, School of Mining, Metallurgy and Chemical Engineering, University of Johannesburg, Johnannesburg 2092, South Africa; and Smith Salifu, Department of Mechanical and Automation Engineering, Tshwane
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