Effect of sliding speed on friction and wear behaviour of nanocrystalline nickel tested in an argon atmosphere
Effect of sliding speed on friction and wear behaviour of nanocrystalline nickel tested in an argon atmosphere
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DOI：
10.1016/j.wear.2007.11.022
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发表时间：
2008-07
期刊：
影响因子：
5
通讯作者：
M. Shafiei;A. Alpas
中科院分区：
文献类型：
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作者：
M. Shafiei;A. Alpas
比较了晶粒尺寸为15± 3 nm、硬度为5.09±0.11GPa的纳米晶Ni和晶粒尺寸为20±5μm、硬度为1.20±0.05GPa的微晶Ni的摩擦系数和磨损率随滑动速度的变化关系。在氩气环境中，以0.2×10−2，0.8×10− 2，3.0×10− 2 m/s三种不同的滑动速度，在2N的恒定法向载荷下进行滑动磨损试验。在任何给定的速度在数控镍磨损损伤较小是由于其较高的硬度和更大的弹性深度恢复比相比，mc镍。在相对较小的范围内，mc Ni的摩擦系数和磨损率与滑动速度无关。然而，同样的滑动速度的小幅增加导致nc Ni的磨损率降低了86%，从3.44×10− 3 mm 3/m降低到0.47×10− 3 mm 3/m，其COF增加了31%，从0.49±0.05增加到0.64±0.06。提出了一个修正的Archard方程来预测镍的磨损率作为晶粒尺寸和滑动速度的函数。增加滑动速度使其越来越难以发生塑性变形的表面损伤的nc镍，因为晶界诱导的变形机制是更难以在较高的应变速率下操作。在最高速度下，产生最少量的碎片，其不足以形成保护性摩擦层，从而导致高COF值。
The sliding speed dependence of the coefficient of friction (COF) and wear rate (W) of a nanocrystalline (nc) Ni with a grain size of 15±3nm and a hardness of 5.09±0.11GPa was compared to that of a microcrystalline (mc) Ni with a grain size of 20±5μm and a hardness of 1.20±0.05GPa. The sliding wear tests were performed in an argon environment under a constant normal load of 2N using three different sliding speeds of 0.2×10−2, 0.8×10−2and 3.0×10−2m/s. The lesser wear damage in the nc Ni at any given speed was attributed to its higher hardness and its greater elastic depth recovery ratio compared to the mc Ni. The mc Ni's COFs and wear rates were independent of the sliding speed over the relatively small range used. However, the same small increase in sliding speed caused an 86% reduction in the nc Ni's wear rate, from 3.44×10−3to 0.47×10−3mm3/m, and a 31% increase in its COF, from 0.49±0.05 to 0.64±0.06. A modified Archard equation was proposed to predict wear rates of Ni as a function of grain size and sliding speed. Increasing the sliding speed made it increasingly difficult for surface damage by plastic deformation to occur in the nc Ni, because the grain-boundary-induced deformation mechanisms are more difficult to operate at higher strain rates. At the highest speed, the smallest amount of debris was generated, which was not sufficient to form protective tribolayers leading to a high COF value.