Effects of mechanical properties and surface friction on elasto-plastic sliding contact
Effects of mechanical properties and surface friction on elasto-plastic sliding contact
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DOI：
10.1016/j.mechmat.2007.07.006
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发表时间：
2008-04-01
影响因子：
3.9
通讯作者：
Suresh, S.
中科院分区：
文献类型：
--
作者：
Bellemare, S. C.;Dao, M.;Suresh, S.
压痕硬度已广泛用于材料表征，并且最近的许多计算研究已经建立了弹塑性机械性能与仪器压痕响应之间的定量关系。相比之下，很少有研究系统地量化塑性变形特性对金属和合金摩擦滑动响应的影响。在尺寸分析和有限元计算的基础上，进行了参数研究，将我们之前的工作扩展到不同的接触摩擦条件。对于各种弹塑性和接触摩擦参数，我们针对各种接触条件建立了闭式通用函数，将弹塑性特性（杨氏模量、屈服强度和幂律硬化指数）与稳态摩擦滑动响应（划痕硬度、堆积高度和整体滑动摩擦系数）联系起来。研究了压头下方塑性应变的分布，以合理化变形模式与弹塑性特性和堆积的关系。同时，针对不同表面摩擦条件下塑性流动特性对摩擦滑动（或划痕）响应的影响进行了实验。对纯铜和黄铜合金进行热处理，以改变屈服强度和应变硬化指数，并通过在表面涂抹液体润滑剂来改变接触摩擦系数。使用纳米压痕测试系统进行摩擦滑动实验，发现晶粒尺寸和合金成分会影响响应。尽管摩擦滑动响应与屈服强度、应变硬化和摩擦的变化总是耦合的，但计算和实验相结合的方法使我们能够隔离每个参数的相对贡献。结果清楚地表明，应变硬化指数的增加可以显着降低堆积高度，这对摩擦损伤的评估具有已知和进一步的潜在影响。 (c) 2007 Elsevier Ltd. 保留所有权利。
Indentation hardness has been used extensively for material characterization and many recent computational studies have established quantitative relationships between elasto-plastic mechanical properties and the response in instrumented indentation. In contrast, very few studies have systematically quantified the effect of the plastic deformation characteristics on the frictional sliding response of metals and alloys. Building upon dimensional analysis and finite element computations, a parametric study was carried out to extend our previous work to different contact friction conditions. For a wide range of elasto-plastic and contact friction parameters, we established closed form universal functions, for various contact conditions, that relate elasto-plastic properties (Young's modulus, yield strength, and power law hardening exponent) to steady state frictional sliding response (scratch hardness, pile-up height and overall sliding frictional coefficient). Distribution of the plastic strain beneath the indenter was studied to rationalize the deformation modes versus elasto-plastic properties and pile-up. In parallel, experiments were conducted for the effect of plastic flow characteristics on the frictional sliding (or scratch) response under different surface friction conditions. Pure copper and a brass alloy were heat-treated to vary yield strength and strain hardening exponent and the contact friction coefficient was varied by applying a liquid lubricant on the surface. Frictional sliding experiments were conducted using a nanoindentation testing system, where grain size and alloy composition were found to influence the response. Although variations in the frictional sliding response versus yield strength, strain hardening and friction were invariably coupled, the combined computational and experimental approach enabled us to isolate the relative contributions of each parameter. The results clearly demonstrated that an increase in the strain hardening exponent can significantly decrease the pile-up height, with known and further potential implications for the evaluation of tribological damage. (c) 2007 Elsevier Ltd. All rights reserved.