摘要
受限于样品表面平整度因素,金属玻璃在原子尺度上的摩擦磨损研究还相当缺乏。本文采用原子力显微镜,基于原子级平整的Pt基金属玻璃,研究了法向载荷和循环次数对金属玻璃在原子尺度下摩擦磨损行为的影响。研究表明:通过Bowden摩擦二项式模型拟合试验数据发现,金属玻璃与针尖对摩时的摩擦因数随载荷的增加呈先减小后增大的趋势,这是因为在低载时,金属玻璃与针尖之间的摩擦以界面摩擦为主,界面摩擦因数与法向载荷呈负指数幂关系,摩擦因数随载荷增加而减小,而在高载时,摩擦机制以犁沟摩擦为主,摩擦过程中的能量耗散主要来源于塑性变形,摩擦因数随变形程度的增加而增大;此外,随循环次数的增加,摩擦因数呈单调减小趋势,且载荷对摩擦因数的依赖性随之减弱,这是因为金属玻璃在原子尺度的变形产生了加工硬化作用,阻碍金属玻璃的持续变形,使犁沟摩擦占比逐渐降低。
Limited by the surface roughness of metallic glasses, there is a lack of studies on atomic-scale friction and wear of metallic glasses. Combined the atomic force microscopy and the atomically flat Pt-based metallic glasses, the effect of load and the number of cycles on friction and wear behavior of metallic glasses are investigated in details. The results indicate that the friction coefficient of metallic glass against the tip decreases first, followed by a gradual increase by fitting the measured data into the model proposed by Bowden. This is because the friction mechanism is dominated by interfacial friction at low loads regime, in which the friction coefficient follows a decreasing trend obeying a negative power law. At high loads, however, the friction is transferred into ploughing-dominated friction mechanism, in which most of the friction energy is dissipated through plastic deformation of metallic glass and thus the friction coefficient increases with the degree of plastic deformation. Another point is that with increasing the number of cycles, both the friction coefficient and the dependence of friction coefficient on load decrease monotonously. This is attributed to the work hardening effect that takes place upon the atomic-scale deformation of metallic glass, which impedes the further plastic deformation of the materials, resulting in the decrease in friction coefficient.
作者
姜杰潇
赖建平
余家欣
胡海龙
王伟
李定骏
JIANG Jiexiao;LAI Jianping;YU Jiaxin;HU Hailong;WANG Wei;LI Dingjun(Key Laboratory of Testing Technology for Manufacturing Process of Ministry of Education,Southwest University of Science and Technology,Mianyang 621010;Analysis and Testing Center,Southwest University of Science and Technology,Mianyang 621010;State Key Laboratory of Long-life High Temperature Materials,Deyang 618000;Dongfang Electric Corporation Dongfang Turbine Co.,Ltd,Deyang 618000)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2022年第13期194-202,共9页
Journal of Mechanical Engineering
基金
国家自然科学基金(51975492)
西南科技大学自然科学基金(19xz7163)资助项目。
关键词
金属玻璃
原子力显微镜
摩擦磨损
法向载荷
循环次数
硬化
metallic glass
atomic force microscope
friction and wear
normal loads
number of cycles
hardening