材料期刊网

采用准连续介质法模拟了单晶Al和单晶Cu纳米压痕实验中的初始塑性变形过程获得了压头在不同压深下的加载和卸载曲线. 在计算得到的载荷-压深曲线基础上, 根据Oliver-Pharr法计算了薄膜材料的接触刚度、纳米硬度和弹性模量,并与相关文献的实验结果进行了比较. 研究表明, 接触刚度--位移曲线呈线性关系;纳米硬度测量中存在尺寸效应, 而在弹性模量测量中却不存在尺寸效应. 单晶Al和单晶Cu纳米硬度和弹性模量计算值分别为(0.584±0.013)和(84.088±0.332) GPa, (0.755±0.027)和(131.833±4.449) GPa.预测值与实验结果吻合, 表明使用该方法预测薄膜材料的纳米硬度和弹性模量是可行的.

Quasicontinuum simulations were performed to study the feature of plastic deformation in the initial stage of nanoindentation test of single crystal aluminium and single crystal copper using rigid cylindrical indenter. The corresponding load-depth loading and unloading curves at different depths were obtained. The contact stiffness, nanohardness and elastic modulus both single crystal aluminium and single crystal copper at different depths were calculated by Oliver-Pharr method. The calculated results using quasicontinuum method were compared with nanoindentation experiments published. The results show that the contact stiffness-displacement relations both single crystal aluminium and single crystal copper are linear. The simulated results indicate that the size effect phenomenon exist in nanohardness measurement both single crystal aluminium and single crystal copper. The nanohardnesses of them are 0.584±0.013GPa and 0.755±0.027GPa, respectively. Size effect phenomenon don’t exist in elastic modulus measurement both single crystal aluminium and single crystal copper. The elastic moduluses of them are 84.088±0.332GPa and 131.833±4.449GPa, respectively. The results calculated using the quasicontinuum method agree with the nanoindentation experiments, indicating that it is reliable and valid to measure the nanohardness and elastic modulus by using this approach.