Microstructures, mechanical properties, and grease-lubricated sliding wear behavior of Cu-15Ni-8Sn-0.8Nb alloy with high
- PDF / 9,066,516 Bytes
- 16 Pages / 595.22 x 790.976 pts Page_size
- 42 Downloads / 211 Views
ISSN 2223-7690 CN 10-1237/TH
RESEARCH ARTICLE
Microstructures, mechanical properties, and grease-lubricated sliding wear behavior of Cu–15Ni–8Sn–0.8Nb alloy with high strength and toughness Jinjuan CHENG1, Mincong MAO1, Xueping GAN1,*, Qian LEI1,*, Zhou LI2, Kechao ZHOU1 1
State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China
2
School of Materials Science and Engineering, Central South University, Changsha 410083, China
Received: 02 January 2020 / Revised: 23 April 2020 / Accepted: 06 May 2020
© The author(s) 2020. Abstract: Alloys used as bearings in aircraft landing gear are required to reduce friction and wear as well as improve the load-carrying capability due to the increased aircraft weights. Cu–15Ni–8Sn–0.8Nb alloy is well known for possessing good mechanical and wear properties that satisfy such requirements. In this study, the microstructure, mechanical properties, and grease-lubricated sliding wear behavior of Cu– 15Ni–8Sn–0.8Nb alloy with 0.8 wt% Nb are investigated. The nanoscale NbNi 3 and NbNi2Sn compounds can strengthen the alloy through the Orowan strengthening mechanism. A Stribeck-like curve is plotted to illustrate the relationship among friction coefficient, normal load, and sliding velocity and to analyze the grease-lubricated mechanism. The wear rate increases with normal load and decreases with sliding velocity, except at 2.58 m/s. A wear mechanism map has been developed to exhibit the dominant wear mechanisms under various friction conditions. When the normal load is 700 N and the sliding velocity is 2.58 m/s, a chemical reaction between the lubricating grease and friction pairs occurs, resulting in the failure of lubricating grease and an increase in wear. Keywords: Cu–15Ni–8Sn–0.8Nb alloy; microstructure; mechanical properties; grease-lubricated wear behavior
1
Introduction
Bronze–beryllium (Cu–Be) alloys are widely used as bearing materials owing to their high strength and hardness, excellent thermal conductivity, and good wear resistance [1, 2]. However, the fumes produced by Cu–Be alloys during processing and the debris derived from friction are harmful to human health. Furthermore, Be is very expensive compared to other elements, such as Ni, Sn, Ti, and Al [3]. To overcome these problems, alternative materials are being investigated. Age-hardenable Cu–Ni–Sn alloys are considered the most probable substitutes for Cu–Be alloys from the perspectives
of strength, wear resistance, production cost, and environmental protection [4]. Cu–Ni–Sn alloys have gained considerable attention since the Bell Telephone Laboratory developed them in the 1970s [5]. Currently, many types of Cu–Ni–Sn alloys have been included in American standards, such as Cu–4Ni–4Sn (UNS C72600), Cu–9Ni–6Sn (UNS C72700), Cu–10Ni–8Sn (UNS C72800), and Cu–15Ni–8Sn (UNS C72900). Among them, Cu–15Ni–8Sn alloy has the optimal mechanical properties [6, 7], which might be close to those of Cu–Be alloy [8]. However, the Cu–Ni– Sn alloys used in bearings for engines and aircraft landin
Data Loading...
