中文摘要：

对KDP晶体二倍频晶面样品进行金刚石球形压头纳米划痕实验,划痕方向为0°、45°和90°,划痕长度为420μm,恒斜率载荷变化范围为0～150 mN,并利用扫描电子显微镜对划痕形貌进行观察。通过对划痕深度-距离曲线及划痕形貌进行分析,获取各划痕方向脆塑去除比例和脆塑转换位置。实验结果表明：0°、45°和90°方向脆塑转变位置分别为209.0μm、158.5μm和112.6μm,从而可知沿0°方向划痕的样品脆塑转变最晚,临界载荷最大,划痕脆性去除最少,是样品的最优加工方向。磨削加工验证实验结果显示,0°方向平均切削力及加工后表面粗糙度均最小,进一步证实其为KDP晶体二倍频表面最优加工方向。

英文摘要：

Nano-scratch test has been conducted on the second harmonic generation（SHG） crystal face of KDP crystal using a diamond spherical indenter with 0°,45° and 90° scratch orientations along a scratch length of 420 μm under a ramp loading from 0 to 150 mN.The scratch morphology was observed by scanning electron microscopy.The starting transition point from brittle to ductile and the brittle and ductile removal proportion were obtained according to the scratch depth-scratch distance curve and the scratch morphology.Results showed that the transition point from brittle to ductile in 0°,45° and 90° orientation was 209.0 μm,158.5 μm and 112.6 μm.0° is the optimal processing orientation because the piece which was scratched in 0° had the latest transition point from brittle to ductile,the largest critical load and the least brittle removal during scratching.The conclusion of the grinding demonstration test was the averaged cutting force and the surface roughness were the least when the piece was machined in 0°.So it was validated that 0° is the optimal processing orientation KDP crystal SHG face.