中文摘要：

通过变深度纳米划痕实验对KDP的断裂特性进行了研究,测量了在KDP晶体（001）晶面上沿不同方向进行划痕实验时首条裂纹出现的位置。随后建立了该划痕过程的有限元模型,计算得到了导致KDP晶体沿不同方向发生断裂时的拉应力,并解释了划痕实验中出现微裂纹和崩坑的原因。结果表明,在KDP晶体（001）晶面上沿0°方向加工时材料最容易发生断裂,对应的拉应力为107 MPa;而沿45°方向时材料表现出较好的可加工性能,此时导致KDP晶体发生断裂的拉应力为160 MPa。

英文摘要：

Depth-increasing nanoscratch experiments along different directions on the（ 001） plane of KDP crystal were carried out and the distances between the first crack and the scratch origin were measured.Then,a FE model of the nanoscratch process was established to calculate the tensile stress leading to crack along different directions. The simulation results have also explained the forming process of the micro cracks and pits observed in the scratch experiments. It is demonstrated that the crystal is more fragile along 0° direction on the（ 001） plane and the tensile stress at fracture is 107 MPa. It performs better machinability along 45° direction and the tensile stress leading to crack is 160 MPa.