摘要
应用有限元方法(FEM)结合神经网络优化及无量纲模型,建立了可统一描述蓝宝石不同晶面纳米压入行为的本构方程。采用纳米压痕方法对蓝宝石晶体的四个典型晶面(C、A、R、M)的表面微力学行为进行了研究,本构方程计算结果与实测结果对比表明:加载、卸载曲线均可由压入深度h的二次函数表达;加载曲线是压入面弹性模量E、屈服应力Y和加工硬化指数n的函数,卸载曲线则除此三个因素之外还与卸载位置(最大深度)h_(max)有关;对同一晶面而言,残余深度hr正比于h_(max),塑性功正比于h_(max)的三次方。结果还表明,对蓝宝石晶体这类难以应用常规力学性能试验研究手段的超硬高脆材料,利用本构方程结合纳米压痕试验,可以比较有效地获得其基本力学性能。
A constitutive equation was established using finite element method(FEM)combined with neural network optimization and dimensionless model to uniformly describe the nanoindentation behavior of different crystal planes of sapphire crystal.The surface micromechanical behavior of four typical crystal planes(C,A,R,M)of the sapphire crystal was studied using nanoindentation method.The comparison between the calculated results of the constitutive equation and the measured results show that:the loading and unloading curves can be expressed by quadratic functions of the indentation depth h;the loading curve is a function of the elastic modulus E,yield stress Y,and work hardening index n of the intrusion surface,while the unloading curve is also related to the unloading position(the maximum depth)h_(max) in addition to these three factors;for the same crystal plane,the residual depth hr is proportional to h_(max),and the plastic work Wp is proportional to the third power of h_(max).The results also indicate that,for super hard and brittle materials such as sapphire crystal,which are difficult to apply conventional mechanical performance testing methods,the combination of the constitutive equation and nanoindentation testing can effectively obtain their basic mechanical property.
作者
刘婷
李先昊
郭耀军
康森
鲁雅荣
何力军
LIU Ting;LI Xianhao;GUO Yaojun;KANG Sen;LU Yarong;HE Lijun(Ningxia Key Laboratory of Photovoltaic Materials,School of Materials and New Energy,Ningxia University,Yinchuan 750021,China;TDG Yinxia New Material Company Limited,Yinchuan 750011,China)
出处
《人工晶体学报》
CAS
北大核心
2024年第6期982-990,共9页
Journal of Synthetic Crystals
基金
中央引导地方科技发展专项项目(2022FRD05036)
宁夏自然科学基金(2022AAC03069)。
关键词
蓝宝石晶体
晶面
纳米压痕
有限元方法
本构方程
sapphire crystal
crystal plane
nanoindentation
finite element method
constitutive equation
