摘要
磷酸二氢钾(KH2PO4,KDP)单晶体的纳米力学特性是研究其超精密加工重要依据之一。试验针对(001)晶面和三倍频晶面采用带有针尖半径为50nm的Berkovich压头的纳米压痕仪对KDP晶体进行力学特性分析,结果表明,两个晶面的纳米硬度H和弹性模量E都表现出强烈的载荷依赖效应。应用Meyer定律和修正比例样件阻尼(Modified proportional specimen resistance,MPSR)模型揭示和说明KDP晶体纳米压痕尺寸效应现象是一种载荷和压痕深度非线性比例阻尼的结果;对加工样件的Raman光谱分析结果表明,加工表面残余应力是影响压痕尺寸效应的非线性程度的重要因素。对材料加载位移曲线的进一步观测发现存在加载突进现象,该现象和材料的弹塑性转变密切相关。
Mechanical properties of potassium dihydrogen phosphate（KH2PO4,KDP） single crystal at the nano scale are one of important factors for probing its ultraprecision machining technology. Nanoindenting tests on（001） crystallographic plane and the tripler plane of KDP single crystal at room temperature are investigated by using nanoindentation tester with a standard Berkovich indenter with its tip radius around 50 nm.The results show that the nanohardness H and elastic modulus E exhibit significant peak load dependence. And the nonlinear proportional specimen resistance of normal load versus contact depth is responsible for the observed size dependence of H and E by Meyer＇s law and the modified proportional specimen resistance（MPSR） model. Furthermore,according to the of Raman spectral analysis,the nonlinear amplitude of them is influenced greatly by the surface residual stress of the processed sample. Moreover,pop-in events are also observed in load-displacement curves,which are closely correlated to the transition from elasticity to plasticity of the examined single crystals.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2010年第17期192-198,共7页
Journal of Mechanical Engineering
基金
国家自然科学基金重点资助项目(50535020)
