刘小明
,
由小川
,
柳占立
,
庄茁
金属学报
利用分子动力学方法模拟了刚性金刚石压头在Ni单晶体上的滑动过程, 讨论了压入深度对
摩擦力的影响(压入深度对滑动过程中压头下方的微结构演化(能否发射位错环)有很大影响). 结
合摩擦过程中的塑性行为和能量耗散机制, 解释了产生摩擦力锯齿形曲线的原因, 证实了位错的形
核及湮灭是黏--滑机制的原因之一. 不同滑动速度对摩擦力影响的模拟表明, 压头的滑动速度决定
了压头下方位错环的运动和演化形式: 在高速滑动下, 形成的位错环依次沿着滑移面很快向Ni单晶
基体内扩展; 在低速滑动下, 压头下方产生的位错环互相发生作用, 在材料的亚表面形成较低能量的
大位错环, 由此产生的塑性变形主要集中在材料的亚表面.
关键词:
纳米尺度
,
Friction
,
Molecular dymamics
,
Stick-slip mechanism
,
Dislocation loop
Xuehua ZHANG
,
Yuanbin KANG
,
Sipeng LIU
,
Qiang LI
,
Ying YANG
材料科学技术（英文）
TaN/NbN multilayered coatings with nanoscale bilayer periods were synthesized at different Ar/N2 flow rate by r.f. magnetron sputtering. XRD and nano indenter were employed to investigate the influence of Ar/N2 flow rate on microstructure and mechanical properties of the coatings. The low-angle XRD pattern indicated a well-defined composition modulation and layer structure of the multilayered coating. All multilayered coatings almost revealed higher hardness than the rule-of-mixtures value of monolithic TaN and NbN coatings. At FAr:FN2 =10, the multilayered coating possessed excellent hardness, elastic modulus, internal stress, and fracture resistance, compared with ones synthesized at other Ar/N2 flow rates. The layered structure with strong mixture of TaN (110), (111), (200) and Nb2N (101) textures should be related to the enhanced mechanical properties.
关键词:
RF magnetron sputtering
,
TaN/NbN多层膜
,
纳米尺度
